I've looked in a few of the obvious places like the wiki, upload guidelines, etc, but I can't seem to find a list of the allowed file types. I assume the upload form tells you if you try to upload something improper, but I don't want to sit and spam the upload form to check a bunch of random files.

Does anyone have a complete list of all of the currently allowed file types for upload?

• png
• jpg
• gif
• swf
• webm

https://e621.net/help/show/cheatsheet#file_types

What about MP4 and the redheaded stepchild of image formats, WEBP? I don't think I've seen an artist use them, but if any of them do, it would be preferable to have the original file instead of converted versions, no?

Kavukamari said:
I've looked in a few of the obvious places like the wiki, upload guidelines, etc, but I can't seem to find a list of the allowed file types. I assume the upload form tells you if you try to upload something improper, but I don't want to sit and spam the upload form to check a bunch of random files.

Does anyone have a complete list of all of the currently allowed file types for upload?

The sites and sources table does also include e621: howto:sites_and_sources#table

OneMoreAnonymous said:
What about MP4 and the redheaded stepchild of image formats, WEBP? I don't think I've seen an artist use them, but if any of them do, it would be preferable to have the original file instead of converted versions, no?

Yes, ideally we would allow all formats and ideally all content is like it was shared initially, but at the same time it's not actually as simple as it sounds, there's some file checks in place for example. Then there are also many fileformats which artists use which are not directly embeddable on webpage also there are actually cases where images are too high resolution and videos are way too high filesize to fit even the already raised filesize limit.

So work with what you got and convert into next best format, with WebP and TIFF, use PNG and with MP4 and AVI, use WebM.

If Wikipedo is anything to go by, the currently best format is FLIF. Lossless, has transparency, can have animation, and other minor features, and beats every other format in file size because it relies more on processing power to decode the image. The only big feature it lacks is sound. Also, having at least one browser adopt it would probably help.

OneMoreAnonymous said:
If Wikipedo is anything to go by, the currently best format is FLIF. Lossless, has transparency, can have animation, and other minor features, and beats every other format in file size because it relies more on processing power to decode the image. The only big feature it lacks is sound. Also, having at least one browser adopt it would probably help.

https://caniuse.com/#search=FLIF
Yeap. We aren't filehost, but public gallery/booru, so users needing to download all everything just to see them - if they can see them considering even majority of mainstream image viewers do not support that format. We will most likely have to deal with flash content somehow in a year or so.

However, also keep in mind that majority of artists are still relying on JPG and PNG and if you look up that table I linked on my previous message, majority of sites where our content comes from only support JPG, PNG and GIF, some websites also offering BMP and TIFF support. So even if we magically did support formats like FLIF, we would technically end up with zero actual content using it unless we have artist exclusively posting the content in that format themselves here first.

This is also why videos are kinda odd thing to handle because flash is dying, but seems like websites aren't in a hurry on improving that, so we have artists pretty much sharing webm, mp4, avi and other fileformats trough filehosts and cloud services instead and at least now only MP4, WebM and OGV are HTML5 compatible containers.

Then this isn't even considering that we go by visual quality, rather than file integrity, so if someone uploads 50 MB PNG first, then someone uploads 1 MB PNG second, we will keep the first upload (situations are handled with common sense and on individual level, just example of what could happen).
e621:image_quality

WebP did actually get huge boost in support as Edge and Firefox both started to support that format in last couple months. However instead of allowing that as uploadable format, we could utilize that for generated samples, which should result higher quality lossy thumbnails and samples with transparency support, while also having smaller filesize.

It'd be nice to have decent transparent_background support in thumbnails, yeah.

Isn't there also the question of whether WebP is going to ultimately replace GIF and APNG (since WebP supports animation -- implemented in recent Chrome + Firefox versions)? If support grows further, this seems very likely to me.

(if you want to check your browser's support for WebP animation, I found this page which has a bunch of side by side gif/webp comparisons. )

[while making this post, I found something weird: compare the results of the search type:gif and filetype:gif . No pagination on the former search.]