Bug overview description.
Every single APNG posted on the site are missing animated tag on the thumbnails.

Also slideshow posts also aren't showing.

What part(s) of the site page(s) are affected?
Post thumbnails.

What is the expected behavior?
There to be "anim" on the thumbnail or alternatively "apng".

What actual behavior is given instead?
Only thumbnail is shown without indicator for it to be animated.

Time of incident (if applicable).
29.3.2018

Can you reproduce the bug every time?
Yes. Animated tag is completely ignored with PNG filetype.

What steps did you take to replicate this bug?
Uploaded post with both animated and animated_png tags. Nothing showed up. Removing animated_png didn't fix the issue either.

Errors or other messages returned (if any).
Nope.

Animated PNG is a lot different than GIF, that being, instead of checking frames, we'd have to parse the whole file. :(

couldn't you just have anything that has animated tag show with the label?

edit:or at least anything that isn't flash/webm/jpeg

Chaser said:
Animated PNG is a lot different than GIF, that being, instead of checking frames, we'd have to parse the whole file. :(

Or just scan for acTL. Should be before the first few bytes according to APNG in Wikipedia

Wait, people actually use APNG?

BlackLicorice said:
Wait, people actually use APNG?

No...

But how does one use it?

Chaser said:
Animated PNG is a lot different than GIF, that being, instead of checking frames, we'd have to parse the whole file. :(

The site checks for the animated tag, not frames or data, according to this thread: https://e621.net/forum/show/247419

Solving this for animated PNG could be as easy as adding "PNG" to an if statement, but it could allow more tagging mistakes to creep in since almost all PNG posts are not animated.

BlackLicorice said:
Wait, people actually use APNG?

As APNG is now more widely supposted and it does have yet another set of advantages and disadvantages over gif, flash and webm/video, it's somewhat useable format in specific cases.

Might be best to add a new label, APNG, so that people seeing the thumbnail label will know it's an animation they can't see if they aren't on Firefox and don't have an add-on

Furrin_Gok said:
Might be best to add a new label, APNG, so that people seeing the thumbnail label will know it's an animation they can't see if they aren't on Firefox and don't have an add-on

https://caniuse.com/#feat=apng
Firefox, safari, chrome or opera.

Takes you back to time when IE6 was a thing, meaning you couldn't use PNG files with transparency or IE6 users would see the images background as black.

But yes, similar to WebM, wouldn't hurt to have APNG tagged.

Gonna go ahead and be one to request that the thumbnail label should read 'APNG' instead of 'ANIM' since apng's do not show their animation on my ipad, would be nice to be able to make the distinction before clicking the thumbnail and thinking the post is still loading after 5 minutes.

I expect many other mobile users would have the same issue.

Maybe the 'ANIM' label should just be replaced with 'GIF', and just identify all animated posts by their filetype?

^ While that initially sounded like a good idea, filetype:gif -animated (that is, the fact that we have 4.6k+ posts that are non-animated GIFs) is a bit of a problem for it.

• "WEBM" is a sensible label because WEBM is animation only, and there are (probably) browsers which don't support WEBM.
• "APNG" is a sensible label because APNG is animation only, and there are browsers which don't support it.
• Maybe "ANIM" should be the label used for any animations which can be considered 'baseline browser functionality' -- ie. if there isn't support for them in your browser, your browser is broken. That covers GIF currently, and might cover WEBM and/or WEBP in the future. (maybe even APNG, but I hope not)

Such a scheme would obviously require checking both the filetype and whether the animated tag is present. Even for APNG and WEBM, animated should not be strictly assumed -- there will always be weird hacks like the GIF Truecolor hack (displays >256 colors by successive placement of frames which each have their own 256c palette)

savageorange said:
^ While that initially sounded like a good idea, filetype:gif -animated (that is, the fact that we have 4.6k+ posts that are non-animated GIFs) is a bit of a problem for it.

• "WEBM" is a sensible label because WEBM is animation only, and there are (probably) browsers which don't support WEBM.
• "APNG" is a sensible label because APNG is animation only, and there are browsers which don't support it.
• Maybe "ANIM" should be the label used for any animations which can be considered 'baseline browser functionality' -- ie. if there isn't support for them in your browser, your browser is broken. That covers GIF currently, and might cover WEBM and/or WEBP in the future. (maybe even APNG, but I hope not)

Such a scheme would obviously require checking both the filetype and whether the animated tag is present. Even for APNG and WEBM, animated should not be strictly assumed -- there will always be weird hacks like the GIF Truecolor hack (displays >256 colors by successive placement of frames which each have their own 256c palette)

Unless somebody successfully comes up with a replacement for APNGs as an "Any color, alpha permitted" aniamated file, I sincerely hope browsers continue to support it. Flash and WebM just don't cut it as replacements.

Well, APNG aren't standardized yet. I'd rather have APNG than nothing, sure. But it would be a lot better to standardize a proper format rather than a hack.