Use of lossy-lossless tag

As I understand it, lossy-lossless currently is used for images that were at least once in JPG format before being converted to PNG, but currently I see the tag also being used on images that fit the search filetype:png jpeg_artifacts -- which is somewhat (?) correct when you stretch the definition enough.

So there are really two cases where I see it confidently used:

• Artist publishes in JPG → user converts to PNG and submits it here (or somewhere, that eventually ends up here by another user). Original is present.
• Artist publishes in PNG → some third-party user/website publishes a JPG conversion → user converts to PNG and submits it here (or somewhere else as above). Original is present.

lossy-lossless images are to be deleted when the original is available, as per how we handle third-party edits, and they are only acceptable when the artist legitimizes those artifacts in their submission by doing a lossy-lossless conversion themselves. It's a apparently sticky situation to me, as we can't assume whether the artifacts are intentionally there as an artistic feature or simply poor handling of their image exporting.

See otto, who seemingly often does this: otto jpeg_artifacts filetype:png.

Will mention some relevant users here who might care, apologies for the notice: @chinatsu (forum #133609, forum #133625) @kittey

Is this a PSA, RFC or request to flag applicable posts when we come across them?

At any rate, I agree with pretty much all you said, except that I think that all of filetype:png jpeg_artifacts being applicable for lossy-lossless is not a stretch of the definition. The way I read the lossy-lossless wiki, it fits perfectly... unless there’s some Photoshop filter for “Add JPEG artifacts to this image for no good reason” without actually saving as JPEG.

kittey said:

Is this a PSA, RFC or request to flag applicable posts when we come across them?

At any rate, I agree with pretty much all you said, except that I think that all of filetype:png jpeg_artifacts being applicable for lossy-lossless is not a stretch of the definition. The way I read the lossy-lossless wiki, it fits perfectly... unless there’s some Photoshop filter for “Add JPEG artifacts to this image for no good reason” without actually saving as JPEG.

Sort of both an RFC and request to flag applicable posts. Perhaps even a request to clarify/rewrite part of that wiki page.

Indeed it does, I just want to clarify that user #118142's usage of the tag is correct, such as on this post. Better yet, would there be a better tag for a post that does have its original JPG uploaded versus if they come lossy-lossless straight from the artist? I dislike assuming things, and like I said before, we can't really assume if the artifacts are intentionally there as an artistic feature (as retarded as that may sound, I know).

This sort of came up as the result of accidentally deleting post #2651474 which I had assumed the parent was the original JPG (it in fact was also marked lossy-lossless). I mostly ask so I'll try not to make the same mistake again.

Mikaeri said:

Indeed it does, I just want to clarify that user #118142's usage of the tag is correct, such as on this post.

I think it is. To me, the lossy-lossless tag means that the image was saved using a lossless format (like PNG) but contains compression artifacts (like JPEG). That should be fairly objective, independent of whether or not the artifacts are there intentionally or who introduced them. The tagger must of course make sure to the best of his knowledge that the artifacts are indeed from a lossy compression like JPEG, not some other image noise.

Also, jpeg_artifacts should only for images where the artifacts are particularly noticeable, so all posts matching filetype:png jpeg_artifacts should be tagged with lossy-lossless, IMHO, but not all posts matching filetype:png lossy-lossless need to be tagged with jpeg_artifacts.

Better yet, would there be a better tag for a post that does have its original JPG uploaded versus if they come lossy-lossless straight from the artist? I dislike assuming things, and like I said before, we can't really assume if the artifacts are intentionally there as an artistic feature (as retarded as that may sound, I know).

When in doubt, tag what you see. :) JPEG artifacts in a PNG? lossy-lossless it is. No assumptions required. (Unless I misunderstood what you were getting at.)

kittey said:

I think it is. To me, the lossy-lossless tag means that the image was saved using a lossless format (like PNG) but contains compression artifacts (like JPEG). That should be fairly objective, independent of whether or not the artifacts are there intentionally or who introduced them. The tagger must of course make sure to the best of his knowledge that the artifacts are indeed from a lossy compression like JPEG, not some other image noise.

Also, jpeg_artifacts should only for images where the artifacts are particularly noticeable, so all posts matching filetype:png jpeg_artifacts should be tagged with lossy-lossless, IMHO, but not all posts matching filetype:png lossy-lossless need to be tagged with jpeg_artifacts.

Indeed... I can only say I fully agree. Albeit I'm fairly unsure as to the level of presence jpeg artifacts have to require tagging it in the image (as I've seen it used for even small amounts of artifacting at times). I'm not an expert on it, but if I can notice it with the naked eye fully zoomed (blockiness and the like) then I usually tag it then and there.

When in doubt, tag what you see. :) JPEG artifacts in a PNG? lossy-lossless it is. No assumptions required. (Unless I misunderstood what you were getting at.)

Nope, you've read me correctly. Thanks for your input as always!

Anyways, I've revised lossy-lossless, lossless-lossy, and help:third-party edit to reflect these stances as usual, although gallery gardening the lossless-lossy tag will be a little bit more difficult, and require more care as it is really subject to user error at times.

EDIT: And adjusted the language (so that only third-party is included, this ignores lossy-lossless/lossless-lossy conversions by the original artist).

I'll be getting to writing more howto's later in the day, just need to finish some stuff off my slate first.