JPEG2000 image read incorrectly

[sl2c]

When doing

from PIL import Image
Image.open('test.jp2').show()

on the file
test.jp2.zip
an apparently incorrect result is displayed.

I have checked this with both the latest Pillow-10.1.0 as well as my reference Pillow-9.4.0: both results are identical and both are incorrect.

[radarhere]

Am I correct in saying that you created this image

but were expecting this?

I see there is a "pclr" box in the image. It looks like an RGB palette that we're not handling yet. Is the image you attached one that can be added a test image, and distributed under Pillow's license?

[sl2c]

I vaguely remember that I got this image from some student lecture notes that were freely distributed on the web. That is to say, I am not the author of this image.

[radarhere]

It seems to me that uclouvain/openjpeg#1463 is relevant, and we might have an easier time addressing this once the next version of OpenJPEG is released.

[radarhere]

It turns out that uclouvain/openjpeg#1463 didn't help.

I've created #7867 to resolve this.