PNGs compression causes no quality loss on the image, JPG compression does.
And if you want to get the iamge better looking, do not add it to the already animated image, but create a new one. The gif is limited to 256 colors only and your already indexed image did not have enough different colors for the new frame, so it looked so bad. After you create a new image, the color palette for it will be different. (balanced better)
Anyway. I like it mucho:P. Gotta say I haven't seen that sig style yet. Though -- but this is probably just me -- I'd love to see the ship's colour match with the background. I think it's something specific to me... just don't like seeing together colours that are not supposed to be.
Well, the original coloring of the Sekhmet is like a gunmetal blue. I really like the gold Anubis/Nephthys coloring more.
When it was the old color, it matched the background pretty well, but it was really boring looking. I also tried making the BG a gold color, but it just was too... gold-y?