Topic: General bug report thread - bugs here, bugs there, bugs everywhere, come here and report your bugs

Posted under Site Bug Reports & Feature Requests

bitwolfy said:
Might be a related issue. For me, there are previews for all of these sites.
Can't replicate the exact problem on my side, though. I used a VPN to get a Brazilian IP address, and I'm still getting the Netherlands server on Inkbunny.

I copy/pasted the question in the helpdesk channel and another user helped me out. It was actually a very interesting fix, it's worth checking out.

gattonero2001 said:
I copy/pasted the question in the helpdesk channel and another user helped me out. It was actually a very interesting fix, it's worth checking out.

I've seen. It's quite fascinating indeed.
Apparently, yes, copy-pasting using a mouse does not trigger the keyup event, which is what the script handling the preview listens for. In hindsight, it kind of makes sense, but it's still kind of strange.
I'll fix it in my script, but it does seem like something that should be handled on the site proper as well.

By the way, I strongly suggest using Idem's Sourcing Suite. It creates a button on many sites (FA, InkBunny, DeviantArt, Twitter, etc) that'll copy-paste all the links and sources for you. It's incredibly handy.

bitwolfy said:
I'll fix it in my script, but it does seem like something that should be handled on the site proper as well.

Is it necessary to open a feature request topic for that? I was hoping that Kira would read through the "adventure" tomorrow.

By the way, I strongly suggest using Idem's Sourcing Suite. It creates a button on many sites (FA, InkBunny, DeviantArt, Twitter, etc) that'll copy-paste all the links and sources for you. It's incredibly handy.

Thank you, I will look into it!

Would you happen to know why URLs from Twitter do not require keyboard interaction, though? Just curious

By the way, I just tested a URL from Inkbunny (the Brazilian version) and the preview did not appear at first, but the keyboard trick worked.

I hope that my avalanche of questions is not bothering you, but is it possible to modify the site proper's script in a way that allows the previewing of Pixiv images without relying on cache?

gattonero2001 said: Is it necessary to open a feature request topic for that? I was hoping that Kira would read through the "adventure" tomorrow.

I don't think so. It's not a feature request, it's a bug report.
Kira does read this thread, AFAIK.

gattonero2001 said: Would you happen to know why URLs from Twitter do not require keyboard interaction, though? Just curious

I have no idea why that works for you without keyboard interaction. It certainly does not for me. ¯\_(ツ)_/¯

gattonero2001 said:
I hope that my avalanche of questions is not bothering you, but is it possible to modify the site proper's script in a way that allows the previewing of Pixiv images without relying on cache?

I seem to have somehow (unintentionally) fixed that issue in re621, so yeah, probably. More research required, though.

Updated

bitwolfy said:
I have no idea why that works for you without keyboard interaction. It certainly does not for me. ¯\_(ツ)_/¯

It actually does not!!! It's very funny in retrospect...

You see, when I copy Twitter URLs they don't come in the "orig" size... so I paste it in the correct place and then I delete the last bit to write "orig" in...

I completely forgot that I did this, sorry...

I seem to have somehow (unintentionally) fixed that issue in re621, so yeah, probably. More research required, though.

Code is a mysterious thing indeed...

Whenever I try using e6 on mobile, tapping on images gives me an "updating posts, 1 pending" message for a split second, and then immediatly changes to "error: " I have to hold down and open them in a new tab to actually look at them. And weirdly enough, if the image has a parent or child post, tapping on them brings me to the image no problem.

rimey said:
Whenever I try using e6 on mobile, tapping on images gives me an "updating posts, 1 pending" message for a split second, and then immediatly changes to "error: " I have to hold down and open them in a new tab to actually look at them. And weirdly enough, if the image has a parent or child post, tapping on them brings me to the image no problem.

There should really be some sort of FAQ section, because things like this keep happening...

I suspect that you might not be in the "view" mode.
Scroll down past all the posts until you see a "Mode" section. It's right above the blacklist, and the tags. Looks something like this: https://i.imgur.com/vy2Pe5k.png
Using a dropdown in that section, switch back to the "view" mode.

onemoreanonymous said:
I bumped into a post #2413373 whose child post #2415521 doesn't show up on that page, but the parent post does show up in the child post's page.

As soon as I read this I thought it sounded suspiciously similar to a problem I once found, so I checked the moderation logs for both posts, and sure enough, post #2415521 has a rejected flag in its history.

Unrelated issue I just found: repeatedly clicking the "Edit" button below an image causes the tags text box to increase in size by a couple of pixels each time.

strikerman said:
Same for me.

If you are in incognito mode, you have to open the image in another tab so that e621 can obtain the preview from your cache. You have to be quick, though, because if you wait too much after loading the original image, Pixiv will block you from viewing it outside the site and you will get a 403 error.

Then you have to copy and paste the address using the keyboard or using a mouse and then interacting with it through the keyboard. I have started doing this and now I have Pixiv previews.

strikerman said:
Same for me.

Pixiv blocks hotloading images from other domains. The only fix for this would be to proxy the image requests through the e6 servers. Since I'm not super interested in supporting proxying arbitrary urls on a whitelist through the server at this time, it's just going to stay broken. Unfortunately FA has also started to do this, so who knows how long it will be before all image previews based on urls are broken unless proxied.

Pictures just stopped loading. When I go to a page it loads everything except the pictures and then keeps loading forever. Download button does nothing. Some pictures on pages I have visited recently still work; presumably they are in my cache memory. This started less than an hour ago.

You can ignore this, turns out the problem was on my end. In my defense some websites were working normally, so I thought e6 was broken again.

Updated

I'm on the fence for whenever it's an actual bug or some hidden feature - since I encounter it from my pc, my laptop, both from my home network and from the other network I have access to (and from Opera VPN, just in case it's some regional punishment) but there seem to be no other reports of that from a quick search glance - but the loading of webm files seems to be broken or something. They load like it's 1996 and I'm on a 56k modem (But both my available networks have internet fast enough to slurp down multi-gigabyte torrent file in mere minutes). The first five seconds or so might load with normal expected speed if the stars are in the right position, but after that it's more like "5 minutes to load 1 more second", and if you use the position slider everything gets broken down to perpetual loading until you reload the page. I can't view any webms as a result, even short 1-second no sound loops aren't always playing.

Updated

darth_e621 said:
I'm on the fence for whenever it's an actual bug or some hidden feature - since I encounter it from my pc, my laptop, both from my home network and from the other network I have access to (and from Opera VPN, just in case it's some regional punishment) but there seem to be no other reports of that from a quick search glance - but the loading of webm files seems to be broken or something. They load like it's 1996 and I'm on a 56k modem (But both my available networks have internet fast enough to slurp down multi-gigabyte torrent file in mere minutes). The first five seconds or so might load with normal expected speed if the stars are in the right position, but after that it's more like "5 minutes to load 1 more second", and if you use the position slider everything gets broken down to perpetual loading until you reload the page. I can't view any webms as a result, even short 1-second no sound loops aren't always playing.

Hmm. Seems to be working fine on my side. Tested the following:

  • MacOS / Chrome
  • MacOS / Safari
  • Windows / Chrome
  • Windows / Firefox
  • Windows / Opera
  • Android / Chrome

Using the blue_hamham hamsters:
post #2367341

It all seems to be working normally. And I wouldn't call my internet speed amazing.

Is it just the webm files that are loading slowly? I'm not sure why it would be just those having issues, and not the rest of the images as well. They are being loaded from the same server.

bitwolfy said:

Is it just the webm files that are loading slowly? I'm not sure why it would be just those having issues, and not the rest of the images as well. They are being loaded from the same server.

Well, now that you're mentioned it, sometimes the images are also loading slower, but by "slower" I mean "not the instant I open the page", so I can't say by how much slower. It never was anything serious so I didn't even notice, only on loading of huge file sizes.

I don't know if anyone else gets this but it forces me to open image posts in New tabs if I just press on the image it says "Error:" it lets me close the pop up but it won't let me open them on that tab. (On moble)

themeliv said:

I don't know if anyone else gets this but it forces me to open image posts in New tabs if I just press on the image it says "Error:" it lets me close the pop up but it won't let me open them on that tab. (On moble)

I answered the exact same question just a few posts ago:

bitwolfy said:
There should really be some sort of FAQ section, because things like this keep happening...

I suspect that you might not be in the "view" mode.
Scroll down past all the posts until you see a "Mode" section. It's right above the blacklist, and the tags. Looks something like this: https://i.imgur.com/vy2Pe5k.png
Using a dropdown in that section, switch back to the "view" mode.

Saving pools with no changes expends credit, also it shows green bar "pool updated" even when there are no changes.

Go to pool, click edit, click update > repeat a dozen times. Now when in edit, just type a in description (to actually edit it) and try to save changes, you get error due to no credit.

kiranoot said:
Pixiv blocks hotloading images from other domains. The only fix for this would be to proxy the image requests through the e6 servers. Since I'm not super interested in supporting proxying arbitrary urls on a whitelist through the server at this time, it's just going to stay broken. Unfortunately FA has also started to do this, so who knows how long it will be before all image previews based on urls are broken unless proxied.

It only needs a "pixiv.com" as referrer for bypass.

aobird said:
It only needs a "pixiv.com" as referrer for bypass.

Which you can't do from a browser. Thus, previews don't work.

bitwolfy said:
This cannot be done via JavaScript, as a security measure: https://developer.mozilla.org/en-US/docs/Glossary/Forbidden_header_name
And doing it server-side - that is, proxying URLs through e621's server - isn't really worth it.

JS has no options for setting parameters for web requests? That link is about modifying, you are still creating the request when user enters a link so you could add it then.

How about getting publicly available preview instead of the link then (link to preview can be easily constructed from given link)?

aobird said:
JS has no options for setting parameters for web requests? That link is about modifying, you are still creating the request when user enters a link so you could add it then.

How about getting publicly available preview instead of the link then (link to preview can be easily constructed from given link)?

You can set request headers in JS. Just not the ones listed on that page. Including when you are creating a request.

Which one is the publicly available preview? I've tried these:

full    https://i.pximg.net/img-original/img/2021/01/04/07/07/15/86806719_p0.jpg
sample  https://i.pximg.net/img-master/img/2021/01/04/07/07/15/86806719_p0_master1200.jpg

But both of those return error 403 when requested outside of pixiv.

aobird said:
Why not?

bitwolfy said:
You can set request headers in JS. Just not the ones listed on that page. Including when you are creating a request.

You can totally set the request headers, but its dependent on where you do it from. For example, in my sourcing suite, I totally set the referer header. But that is because I use the XMLHttpRequest exposed through a userscript manager, not the builtin one. If I try and do the same thing with some javascript through the developer console, it fails instead:

const failing_request = new XMLHttpRequest();
failing_request.onload = (e) => { console.log(failing_request.status, failing_request.response) };
failing_request.open('GET', 'https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest');
failing_request.setRequestHeader('referer', 'http://google.com');
failing_request.send();

// Refused to set unsafe header "referer"

Making a request the way you did AoBird is not the same as making it in javascript through the page served to the user. Your way has elevated privileges and removes security restraints.

Updated

bitwolfy said:
Which one is the publicly available preview?

I don't remember.

https://i.pximg.net/c/48x48/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/128x128/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/240x480/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/250x250_80_a2/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/360x360_70/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/540x540_70/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/540x540_10_webp/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/600x600/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/600x1200_90/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/600x1200_90_webp/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/1200x630_80_a2_g2_u1/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/c/1200x1200/img-master/img/2021/01/01/04/55/46/86711582_p0_square1200.jpg
https://i.pximg.net/img-master/img/2021/01/01/04/55/46/86711582_p0_master1200.jpg
https://i.pximg.net/img-original/img/2021/01/01/04/55/46/86711582_p0.png

I checked those now but they are all locked, I think it should have been at least one of them.
I don't see any other links atm though. Didn't dig too much either though.

idem said:
You can totally set the request headers, but its dependent on where you do it from. For example, in my sourcing suite, I totally set the referer header. But that is because I use the XMLHttpRequest exposed through a userscript manager, not the builtin one. If I try and do the same thing with some javascript through the developer console, it fails instead.

Huh. I wasn't aware of that – but then again, greasemonkey's xmlhttprequest does not work quite the same as the normal one.
But yes, apparently you can set both the origin and referer headers using that method. I'll see if I can use that to load pixiv's previews in my own userscript.

I'm a big fan of your work, by the way. I don't think that I can go back to uploading without using your sourcing suite.

aobird said:
I checked those now but they are all locked, I think it should have been at least one of them.
I don't see any other links atm though. Didn't dig too much either though.

Yeah, all of those seem to return 403 for me as well.
However, when you link a post in Discord, the preview it shows is served from another domain:

https://embed.pixiv.net/decorate.php?illust_id=86711582

Could be something to that. I'll investigate further.

Another interesting thing I've noticed is that even through pixiv's previews are broken on e621, its duplicates search works just fine. I wonder if that service spoofs the referer to download the image, or if it works in a different way.

I don't know if any of you do, but when I'm uploading an image to the page, it takes an eternity to upload

I don't know if this counts as a bug, but I no longer appear to be able to edit as many pools within an hour as I once was able to. I used to be able to make at least 10 changes per hour to pools, but now it seems I get an "hourly limit" error after making changes to only 3.
Is this an intended change, or is something wonky going on. I'm also hoping this isn't some kind of user-specific punishment for pool changes that I'm receiving.

Edit: Things seem to be fixed now as far as I can tell. Not sure what was going on.

Updated

Hard to believe this hasn't been reported but nothing's coming up in the search:

The pool gallery view with Category blank only shows Series pools (i.e. Collection pools are hidden). This is true whether I simply click the Pools link at the top of the page or manually switch the Category dropdown a few times.

I noticed some seemed to be missing a while ago but only just realized it's the Collections (in part because some are comics that probably ought to be Series, like pool #22261).

Not sure if it's always been this way, or if I just noticed it, but the pool navigation links on a post above the image is missing a "first" link despite having "last", "next", and "prev" links. Aside from making it less convenient to get to the start of a pool, it also causes the centered pool title to be misaligned with the search header title. Example being on this post.

I’m using an iPhone 7. When you’re logged in, the size option dropdown goes past the right of the page.
This makes it pretty difficult to scroll down without zooming out all the way, I’ve found. This happens on, if not all, the vast majority of posts, on all browsers I tried.
I don’t know if this was reported yet or if I’m doing something wrong user side but I’d like to see a way around it. Thanks!

Unsure if this is a bug, oversight or intentional design, but if I ever sort by order:score the ‘next/prev’ buttons do not show up, and I can’t use the swiping gestures to scroll through posts, and have to back out of the post to go to a different one.

henhen129 said:
Unsure if this is a bug, oversight or intentional design, but if I ever sort by order:score the ‘next/prev’ buttons do not show up, and I can’t use the swiping gestures to scroll through posts, and have to back out of the post to go to a different one.

It's intentional.

I don’t know if this is a bug but whenever I try to message someone the option to message them doesn’t appear. My mail isn’t even an account option that I can go to. How can I fix this?

https://e621.net/wiki_pages/9169
https://e621.net/help/cheatsheet

The cheatsheet needs a look. It has multiple incorrect or missing metatags. I would make corrections but the page is locked.

  • order:comments and order:comments_asc don't work anymore. order:comment_count works. order:comment_count_asc also works (e.g. pool:22483 order:comment_count_asc).
  • randseed is not listed.
  • approvedby does not work. The correct metatag is approver.
  • User pages link to fav:user instead of favoritedby:user. Both could be listed, with a short explanation of the difference.
  • Opinion: The table row demonstrating the range syntax should show something like score:1..100 or filesize:200KB..300KB as additional examples. See topic #28329
  • notes search may not work at all.
  • Typo: notelocked::true -> notelocked:true
  • hideanon:true and hideanon:false don't appear to do anything. Admin only? Same with hidegoogle.
  • Pool example doesn't work ("Fox and the Grapes"). Same with the set example. These can be replaced with new examples.
  • order:desclength and order:desclength_asc don't work.

Updated

@bitWolfy
I strongly suspect Twitter doesn't support hotloading either, and it only worked until now because of image cache.
In Firefox v85 they added separate caches for each website for security, and Twitter upload previews stopped working for me
Screenshots: Chrome vs Firefox
Not using any extension
Edit: Mozilla calls it "Network Partitioning"

Updated

I updated an artist page and it did the thing where the list of artist's URLs inverted, so that the order of urls you intended to enter is reversed. Making an edit to try to trigger the reversal again (since I know this would happen everytime the page was edited before the site overhaul last year) did not work, nor did reverting the edit (which shows up as a new edit altogether.

Since artists usually don't update all of their art sites at equal rates, this seriously affects the organization of artist pages.

If you try sending a DMail to someone who's blocked you, the error reads "Error: To name does not wish to receive DMails from you"

hey i have a little problem i have blacklisted 2 artists but they are still showwing up when i look at the pages what do i do?

q1k5 said:
hey i have a little problem i have blacklisted 2 artists but they are still showwing up when i look at the pages what do i do?

Reply or dmail me with your blacklist.

The problem is probably that you put them on one line. You need line breaks between them.

If your blacklist has artist1 artist2, it will only work if both artists are tagged on the same image. You need to have:

artist1
artist2

on separate lines to block all images by artist1 and artist2.

Updated

1- If the edit button in the post is clicked again after opening the edit window, it will only slightly expand the edit window and not closing it.
2- On pc, in window mode, when browsing posts, shrinking the window causes some overlappings among the ad, the posts, and also sometimes with the search bar.
3- When a wiki containing blacklisted thumbnails is opened with the blacklist activated, and then the blacklist is deactivated, causes the blacklisted thumbnails to stretch weirdly and not show. Same thing, having the blacklist deactivated and then activate it causes the blacklisted thumbnail to stretch and not censor. (reloading the page fixes it)
4- There is also a bug when I opened a webm on mobile where the box behind the video started to rapidly disappear and reappear causing lag, I had this bug only once with this post: post #1402994
5- I don't know if it's a bug, but when editing the blacklist or the tags in a post, writing a tag and then selecting the suggested tag causes the whole line of tags below to connect with the current line of tags (works only if the tag that is added is the last tag of the line).
this is frustrating especially when editing the blacklist.

Updated

Images aren't loading for me on both desktop and mobile. I can't even see them when I go to click on them. When I wait for them to load, I just get broken images.

grave_mind said:
Images aren't loading for me on both desktop and mobile. I can't even see them when I go to click on them. When I wait for them to load, I just get broken images.

Aaaaand of course, now everything's fine. Must've been a hitch in my connection or something. Disregard!

Not sure if this a bug or not: blacklisting image scores don't seem to work. If it is a coding error then it's been overlooked for quite awhile. Like I've said in the first sentence, I don't know if it's a glitch or not - if the feature is caused by a coding limitation, I'll apologize for the bug report

steel_snake said:
Not sure if this a bug or not: blacklisting image scores don't seem to work. If it is a coding error then it's been overlooked for quite awhile. Like I've said in the first sentence, I don't know if it's a glitch or not - if the feature is caused by a coding limitation, I'll apologize for the bug report

Please, provide the blacklist line that you are trying to use.
For example, blacklisting score:<=-20 works perfectly fine for me.

bitwolfy said:
Please, provide the blacklist line that you are trying to use.
For example, blacklisting score:<=-20 works perfectly fine for me.

Well, it was score: <-1, but I now realized that it's my fault, I put a space in it. I am a bit stupid at times, sorry for the false bug report

steel_snake said:
Well, it was score: <-1, but I now realized that it's my fault, I put a space in it. I am a bit stupid at times, sorry for the false bug report

It's all good, happens to the best of us sometimes.

onemoreanonymous said:
I noticed that the last 5 images displayed in this search for posts with more than 1 artist tag have a single artist each.

https://e621.net/posts?tags=arttags:%3E1%20order:score%20rockbottomfeeder

Seem to be working for me, could've been a processing error and the servers got confused for a bit. Though it could be an account based error. Not entirely sure if it's what I've listed above, I am not expert at coding so I am going off past experiences with other websites.

onemoreanonymous said:
I noticed that the last 5 images displayed in this search for posts with more than 1 artist tag have a single artist each.

https://e621.net/posts?tags=arttags:%3E1%20order:score%20rockbottomfeeder

Fixed it.
It happened because the post had the artist's previous tag - mistermead. Since the tag was later aliased to rockbottomfeeder, only the latter was displayed. However, the old tag was technically not removed, so the system thought that both of those tags were present. Thus, arttags:>1 matched it.

bitwolfy said:
Fixed it.
It happened because the post had the artist's previous tag - mistermead. Since the tag was later aliased to rockbottomfeeder, only the latter was displayed. However, the old tag was technically not removed, so the system thought that both of those tags were present. Thus, arttags:>1 matched it.

Huh, interesting

The DText syntax for search links with a custom title doesn't work. The DText help page displays the problem.

{{a list of tags|Some Text}}

should result in Some Text, but you get Some Text instead. The DText for wiki links with a custom title work, though.

The tags icelynn_(time_majesty_ruffus_adventures and cactivil_(time_majesty_ruffus_adventures) show up in the tag list with one post each, but nothing shows up even with status:any.

It is NOT simply a case of a lack of tag number update, because searching for them in "Post Changes" under "Final Tags", "Added Tags" and "Removed Tags" returns nothing.

A similar issue applies to ~rose~ and ~read, but in those cases it is understandable because of the initial ~.

I feel like I'm missing something obvious here, but for a while I've noticed that the number of images listed as being under a given tag doesn't always match the visible images. Yes, I'm logged in, no, I have nothing blacklisted. As an example, this image https://e621.net/posts/1978736. If you click the character name (65 instances) you get 64 thumbnails, the image in question being the missing 65th.

Edit: I ctrl-f5'd it to see if it was a caching issue and the image appeared in the thumbnail list...but there's still only 64 images.

tredfg543 said:
Look at the results from this search:

https://e621.net/posts?tags=id%3A2624582

The thumbnail is sideways, though the image is rendered correctly when you click on it. I don't think I've ever seen this behavior on esix before....

Both look sideways to me. Doesn't matter if I set the image size to original, fit horizontal, fit vertical, or sample.

My blacklists aren't working on mobile for some reason. They're working fine on desktop, but if I go on mobile, I might as well not have them on at all.

grave_mind said:
My blacklists aren't working on mobile for some reason. They're working fine on desktop, but if I go on mobile, I might as well not have them on at all.

Disregard. I'm an idiot. Didn't know I had my blacklists disabled. Carry on.

watsit said:
Both look sideways to me. Doesn't matter if I set the image size to original, fit horizontal, fit vertical, or sample.

Might this be browser-specific? On Chrome I see the thumbnail sideways, but the full-size image right-way-up. However, if I switch to the "sample" view it goes sideways.

At a guess, this image is natively sideways, but has EXIF data indicating a 90-degree rotation is needed. The esix thumbnail ignores and discards EXIF, as does the Sample view, but on viewing the full-size image Chrome is honoring the embedded EXIF.

On one hand, leaving the uploaded asset alone bit-for-bit is reasonable behavior, not least because then you can rely on hashes to identify content. On the other hand, it would seem to me that either stripping out or refusing uploads with EXIF rotation data might be a good idea.

tredfg543 said:
On one hand, leaving the uploaded asset alone bit-for-bit is reasonable behavior, not least because then you can rely on hashes to identify content. On the other hand, it would seem to me that either stripping out or refusing uploads with EXIF rotation data might be a good idea.

The correct answer seems obvious from your post: if EXIF rotation data is present, the thumbnail and sample converter should either preserve it or rotate the image itself, since thumbnails cannot and should not bit-for-bit match original images anyway.

wat8548 said:
The correct answer seems obvious from your post: if EXIF rotation data is present, the thumbnail and sample converter should either preserve it or rotate the image itself, since thumbnails cannot and should not bit-for-bit match original images anyway.

Except apparently some browsers don't honor the EXIF rotation data, and the full size image shouldn't be re-encoded with rotation preapplied, making that not viable (unless it can be done losslessly?). Stripping out the EXIF rotation data (to ensure uniform behavior) or refusing uploads with EXIF rotation data (since it would appear wrong for some people) are the only options left.

watsit said:
full size image shouldn't be re-encoded with rotation preapplied, making that not viable (unless it can be done losslessly?)

PNG is lossless. Barring software bugs or a bad implementations of something like JPEG decoding, any image can be decoded-to-bitmap, rotated, and losslessly re-encoded to PNG. Filesize will be much larger than something like JPEG, and hash will obviously not match the original source.