XnView Software

XnViewMP 1.4.3 64bit
Windows11 (22H2), display resolution 3840x2160, win scaling 150%

Viewer
copy-pasting 4-8bit images is corrupted

To reproduce:
1. run clean portable XnViewMP

Issue A
2. open test image (4bit, 8colors, 1transparent index) 3. make any selection
4. press CTRL+C, CTRL+V
- pasted data will be corrupted (as result colors quantity increased to 16)
- image will turns into 32bit XnView Classic also pastes black data, but if saved and reopened - there is no issue, bitness preserved, pasting only messes if selection area differs (which is understandable).

Issue B
2. open test image (8bit, 256colors) 3. make any selection
4. press CTRL+C, CTRL+V
- pasted data will be corrupted (as result colors quantity increased to 461)
- image will turns into 32bit No such issue is XnView Classic, image preservs same bitness, pasting only messes if selection area differs (which is understandable).

Thanks to your detailed description I can reproduce "pasted data will be corrupted"

When you paste, image is always converted to 24/32bits.

See issue for current status and some details.

(In Classic there is some issues when pasting 24bits or different colormap image, so in MP image is always converted in 24/32bits)

This problem is supposed to be fixed in XnView MP 1.5.0 beta. Please check and confirm the bug fix here.

fixed in 1.5.0