1.9.5: Slow rendering speed of JXL images

[drey]

XnView: MP 1.9.5 - 64-bit
OS: Windows 10 - 64-bit

XnView render JXL images much slower than JPG.

Effect:
- Slow rendering speed when switching between JXL images in full screen
- Slow creation/generation speed of thumbnails for JXL files
- JXL thumbnails load noticeably slower (than JPG) when opening folder with lot of JXL files

[xnview]

JPEG XL is slower to decode than JPEG