Interesting that a lot of the letterboxed caps look squashed as well
NTSC pixels are slightly taller than they are wide, so when you display a screenshot at "native resolution" (maintaining the number of pixels) using a computer screen's square pixels, you get a slightly vertically squashed picture.
Displaying a PAL capture might display the opposite problem (but only when captured at 720x576 pixels - captures at 768x576 pixels will have square pixels anyway).
DE