XnView Software

XnView: MP 0.99.6 - 64 bit
OS: Windows 10- 64bit

Neither removing the alpha channel nor extracting the alpha channel is correct with this 8-bit index png. ↓This is the source image

this image file doesn't contain alpha channel but a transparent index that you can change in 'edit colormap'

xnview wrote: Tue Jan 04, 2022 4:46 pm this image file doesn't contain alpha channel but a transparent index that you can change in 'edit colormap'

But it can extract RGB channels.
Why not convert to a 32-bit image and then extract the Alpha channel ?

And I found 'edit colormap' does not establish a record of modifications and cannot be undone after reading the index file of other images.

Thanks to your detailed description I can reproduce the problem.

This problem is supposed to be fixed in XnView MP 0.99.7. Please check and confirm the bug fix here.