XnView Software

XnViewMP 1.8.0 64bit
Windows11 (23H2), display resolution 3840x2160, win scaling 150%

Browser - thumbnails
transparency is ignored for paletted images depending on image size and Catalog On/Off it could be the same issue as:
Browser not showing transparent png files correctly


Issue A - Catalog Off
144px threshold

Issue B1 - Catalog On
216px threshold
Issue B2 - Catalog On - inconsistency of thumb building
1. open folder with test images
thumbnails will be build and look like in B1
2. goto Settings > Catalog
- press Rebuild thumbnails
3. close app
4. open folder with test images
thumbnails look like in A
5. run View > Rebuild thumbnails
thumbnails look like in B1 again


expected behaviour
thumbnails should always show transparency




Related

• issues
  1.7.2 - browser - thumbnails - issue with embedded thumbnails
  - done -
  1.6.5 - view - transparent index visible when zooming (1.8.1)
  1.8.0 - browser - thumbnails - paletted images transparency ignored (1.8.1) current post
  1.6.4 - browser - thumbnails - cached size affects size of some thumbnails (1.6.5)
  1.5.3 - browser - thumbnails - autorotation (1.6.0)

Thanks to your detailed description I can reproduce the problem.

just realized that it also depends on win dpi scale (150% in my case)

This problem is supposed to be fixed in XnView MP 1.8.1. Please check and confirm the bug fix here.

fixed in 181