as a guess as to which formats used:
4. JPEG-LO, appears blocky.
5. ANI-FRAME, made obvious by the limited color pallet, results in banding, may look better with dithering, but that isn't the point of the exercise...
1. 2. 3. are indistinguishable to me, being unable to tell the difference between PNG and BMP is expected, as both are lossless formats. However, 1. appears slightly more vibrant, and due to being the different different one of three, I would expect this one to be JPEG-HI, however, this may just be because of what Rga_Noris has said.
hell, any* 24 bit (32bit? possible transparency suppourt?) image format would be better than what's being used at the moment :\
*hyperbole.