JPEG 2000 file cannot be Image.reduce() 'd

[Eximius]

JPEG 2000 file cannot be Image.reduce() 'd

... because img.reduce becomes a integer 0 during loading somehow.

Can be repeated with

this image

$ python -c 'import PIL;from PIL import Image; im = Image.open("pillow_bug.jp2"); print(PIL.__version__);print(im.reduce)'
7.1.0.dev0
0

[radarhere]

Hi. Thanks for reporting this. The bug you've found applies to Jpeg2000 images. #4251 added an Image reduce method which is here overlapping with Jpeg2KImagePlugin's reduce property. I've created PR #4344 to resolve the situation.

In the meantime, you can workaround this by simply copying the image first -

from PIL import Image
im = Image.open("pillow_bug.jp2")
im.copy().reduce(2)

[homm]

Unfortunately, this breaks a very common use case:

Image.open("pillow_bug.jp2").thumbnail((100, 100))

because thumbnail now uses .reduce() method internal.