OK, this is getting confusing. The same 1600 x 1200 image
looks just fine when I convert it to JPG format first (all the previous tests were with BMP's, I probably should've mentioned it
).
It seems that not all BMPs exhibit the problem. I tried a hi-res version of The Dark Side of the Moon album cover (it'd easy to see if its image is shifted), 1600 x 1200 (see attached). Both the JPG and the BMp work just fine.
I'm confused.