Tried png, after I had to resize my signature (the almighty Xris ordered me to do so
)
the original GIF I used (68825 bytes)
a 100% jpeg of the same image (78070 bytes)
the png I made out of the same source as the gif (148192 bytes) also, transparency did not work in this image
in the end, the png was more than twice as large as the gif. So I went for a jpg of 30 KB.
Flash: As for the quality of the gif in Photoshop, PS has several palettes, my guess is you (or the program) picked a wrong palette