Lossless jpeg xl images not rendering correctly in Preview on macOS 15.7

dialabrain wrote:

FWIW, the edge artifacts only appear with certain viewers. They are not created using JPEG XL.

I figured it out. You also need a non-photographic, non-transparent image. It could happen on photographic images too, but it would be too difficult to see. I could only recreate the effect when using a solid background. If the image is transparent, then it's fine.

Perhaps it's an aesthetic thing. Apple detects that you've got a non-photographic image with a background that you've saved as JPEG. They must figure that you want that "JPEG effect" with artifacts around the hard edges. Otherwise, you would have used transparency to avoid that.

FWIW, I created multiple files using different apps; pngs, tiffs and bmps, then converted them to jxl files using Acorn and GC12. All with the same results as I mentioned. Some viewers showed an artifact, some didn't, on both Sequoia and Tahoe.

An example from the OP would certainly help. I can't see a problem in Sequoia or Tahoe.

Just to add, creating/converting/saving images with different color profiles would certainly affect things.

Just thought I would mention Firefox and Brave do not support JPEG XL. Safari does. It's not a format that is commonly used. WebP does nearly the same compression and most everything supports it.

FWIW, I created a red circle on white. Saved as png. Converted it to jxl in GC12 and it shows a border in Preview.

Could you provide a bit of clarification. I'm confused about something really important.

You're complaining that Preview in macOS 15.7 and earlier cannot correctly jpegxl images. So what's Apple supposed to do then? Release a new version of the operating system?

etresoft wrote:

I found a lossless jpegxl and it looks fine. When zoomed way in, I still see all the pixels.

Yes well, that wasn't the OP's issue…

"Clearly the chroma bandwidth has not been recreated. The result is that colours leak out in to each other and white areas."

dialabrain wrote:

Yes well, that wasn't the OP's issue…

"Clearly the chroma bandwidth has not been recreated. The result is that colours leak out in to each other and white areas."

Every year there's a few people with images that have unusual colorspaces or oddball formatting and don't display properly in Apple Preview. I've only seen a couple of instances where they've provided an example. That makes it easier to reproduce the bugs. But I haven't seen anyone determined enough to make it through a whole year with one of these bugs to see if it gets resolved the next year.

tangyminty wrote:

No it's not, look again. I made the screen shot. The top left image is from apple preview. Graphic converter at the bottom shows the jpeg xl correctly. I can export the displayed image from preview as a PNG and it is still wrong.

You're correct. It looks like you used GC11 to create the screen shot. Obviously you should update. That being said, Here is a screenshot of Preview displaying a png on the left and a jxl file on the right. They look identical…

[Edited by Moderator]

Aha! We might be getting somewhere. Your Apple logo images are not the same. The .jxl image on the right has the same type of dark and light edges that aren't on the .png image.

I tried saving a PNG out of GC 12.x to see if that's the cause, but it wouldn't let save a .jxl image without a license for the app.

Kurt Lang wrote:

Aha! We might be getting somewhere. Your Apple logo images are not the same. The .jxl image on the right has the same type of dark and light edges that aren't on the .png image.

No we aren't lol. That's the shadow of the window overlapping the png. All windows have them.