Source: http://www.unrealadmin.org/forums/showt ... hp?t=29936Problem: your monitor supports a resolution of 1366x768 (16:9) but if using that value for UT, the screenshots will get corrupted.
Reason: UT doesn't follow the BMP specifications that each pixel row's data must be padded to multiples of 4 bytes. If your horizontal screen resolution isn't dividable by 4 then the screenshot BMP file will be off-specs. (Wormbo)
Solution: be sure your horizontal screen resolution is a multiple of 4. 1366/4 = 341.5!
Either 1280x720 or 1360x768 should work fine for 16:9 screens.