Images not showing in preview but display correctly in fullscreen

[bobik3]

Images aren't showing up in the preview, but they display just fine in fullscreen mode.
Maybe there's a setting to enable transparency that I missed.
I'd appreciate any help. I don't think it's a bug, probably just a setting I overlooked.

[user0]

share example file

[bobik3]

for example:
https://www.mediafire.com/folder/mojozc8w4xhzr/Camera

[user0]

you unchecked 'Use alpha channel' in Settings>Thumbnails (checked by default)
so thumbnails were generated w/o alpha channel

however, there is still an issue with rendering png with disabled alpha channel (test_img_10 + zoom + antialiasing + Ctrl+H)

upd: I'm starting to think the only reason of your posts - to promote crappy paid +18 browser game via spam/ceo link in signature
smells like a ban