[Feature] Support JPEG XL images

[JadedMagician]

Discussed in https://github.com/stashapp/stash/discussions/3324

^{Originally posted by DevonAA December 31, 2022} It seems stash app does not recognize the JPEG XL image format.

With "jxl" added as image extension the log shows: error processing "<path>.jxl": decoding image file "<path>.jxl": image: unknown format

I've converted all my images from JPEG to JPEG XL a long time ago and saved 1 TB+ disc space with zero (lossless) quality loss. Will definitely not convert back to an older worse format.

From what I understand the stash app uses FFMPEG. Good! A quick internet search tells me FFMPEG added JPEG XL support ca. 6 month ago - so that should be no problem - I've updated it a few days ago.

Because I use FFMPEG for many things I just copy the exe it into C:\Windows. Not sure if stash uses that one or maybe it comes with it somehow packed into "stash-win.exe" !?

Any idea how I can verify what FFMPEG version stash app is using? (To check for JPEG XL support)

Online JPEG XL converter for tests: https://jpegxl.io/

Apple is currently rolling out support for JPEG-XL across both macOS and iOS, including Safari, which makes up 20% of the browser market. In light of that, now would be a good time to consider adding jxl support to Stash. JPEG-XL can losslessly compress JPEG files by 20-50%, which would be incredibly useful for those of us that have large image collections.