Is it safe to tag from thumbnail using mode edit? Of course, I'm talking about things that can be easily seen from the thumbnail. I'm asking that, because I think I've seen people saying that it isn't reliable, but why? I know there are posts with an incorrect thumbnail, but are they that common that would hinder the use of mode edit?

gamemaniac 2.0 in the making

Ratte pretty much brings it to a point but considering this deep e621 lore let me elaborate:

Thumbnails can be deceiving, particularly if you're trying to go fast. Even obvious things can be, at a glance, incorrect. The loss of information from the smaller dimensions plus compression can be enough to hide crucial details. Gamemaniac now was a person that unrelentingly used that feature to the point where we had to ban him because he just didn't care about the mistakes be made along the way.

Instead of relying on it solely use it as a complementary tool, for example if you've verified a bunch of posts to deserve the tag changes you can use it to quickly make the changes from the index. But relying solely on it can end badly.

sieghelm_lockayer said:
Is it safe to tag from thumbnail using mode edit? Of course, I'm talking about things that can be easily seen from the thumbnail. I'm asking that, because I think I've seen people saying that it isn't reliable, but why?

The main reason I could think of is because thumbnails can distort the image in interesting ways, making it look like it contains one thing but is actually something else when you see it at a more normal size. There is the misleading thumbnail tag, though it's likely not on all images that it would be affected.

If you really took your time inspecting a thumbnail you could probably tag the "things that can be easily seen" but in the same time you could've just opened the image and looked at the full resolution version. Some things are just very easy to mistake, especially now thumbnails are cropped.

If you want to edit a lot of posts fast I'd recommend bitWolfy's TagMe! tool since it actually uses large previews not tiny thumbnails.

Eh, thumbnails rarely convey accurate details that might be worth tagging and could result in mostly false and unfitting tags to be set on the post, but this sometimes varies on how complex is the image in question, wouldn't recommend doing it really.

Never tag by thumbnail, actually take the time to look into the post and add in the tags.
Only use that Edit mode feature if you're extremely certain that's the case for the tag you're adding (e.g., blanket tagging year tags on your own posts).

thegreatwolfgang said:
Never tag by thumbnail...

Too late I tagged by thumbnail approximately 50-60% of 800 posts with single tags, 2 months ago. I rechecked every single one of these changes and the only ones that seemed to have some kind of problem were the posts where I added single abs tag.

These are the posts that looking now I'm not sure I should've tagged them as abs and should've skipped instead and just two of those were tagged from thumbnail, as far as I can remember and some I pretty sure I clicked before tagging it:

faucet said:
If you really took your time inspecting a thumbnail you could probably tag the "things that can be easily seen" but in the same time you could've just opened the image and looked at the full resolution version. Some things are just very easy to mistake, especially now thumbnails are cropped.

Ofc, I already know what I'm looking for when I tag that way. It's not as if I'm going into random images and tagging EVERYTHING in the image from the thumbnail. If I want to, for example tag blue_sky, cloud or day, I can search for -day -blue_sky -sunset -sunrise -night -cloud outside and then look for posts that fit my criteria, which is pretty easy to spot, if I have any slight doubt I just skip the post. This is faster than to click on the post, wait for the image to load, tag it, click on submit, wait for the page to load, click on the tags history to see if I didn't screwed something, wait it to load, come back at the post, wait it to load enough to see the "next" button and finally go to the next page and repeat...

While tagging from the thumbnail, I can just burn my entire hourly tag limit in 20-30 minutes which helps me keep track how many posts I changed AND also gives me time to review all my changes from my profile instead which saves a TON of time.

But anyway... I think I'll just use this more sporadically now, thanks for all the responses and if someone could give a look at the posts I linked and tell me if it's mistagged or not that would be nice. I learnt my lesson. Thanks, again. (⠀👍⠀.⠀⠀_⠀.⠀)

I've tagged some very broad things like rear_view off a thumbnail.