Blocky alpha-artifacts, webp save, Pillow: 10.3.0 about pillow

[radarhere]

Could you upload a copy of the original image?

[MvGulik]

Odd ...

Did some additional testing on some test image. (gimp created)
Odd thing here is that if I open the output webp image with pillow and show() it. It looks ok. (shown as png ofc)
Same thing when I open the output webp image in gimp. It also looks ok.
But when viewed two other apps. It shows alpha-artifacts. (Merged_screenshots image)(Nip2 & gThump(bottom-left)

Related used code:

im = Image.open('.../test_circle(in).png', mode='r', formats=None)
im.save('.../test_circle(out).webp', 'webp')

Images:

[MvGulik]

... are those other apps potentially using some outdated webp support code ?

• Shows ok too with Imagemagick. So guess its not a Pillow thing, but related to the used webp code/package in the other apps.