I have finished designing and implementing my ProSonic sprite format into the ProSonic engine. The format encodes sprites in 18-bit color and supports up to 65,535 sprites. It also has mirror and flip flags. In addition, animations are also incorporated into the format with up to 255 frames supported for each animation, and 255 different animations. Animation speeds range from 0 to 255 (measuring frames).
To test the format, I updated the old object code for rings. It displays flawlessly. The sprite blitting code I wrote in the engine also supports 64 levels of translucency which works really well, even when dealing with just 64 available colors in a zone (which surprised me).
The rings animate at the same speed as they do in the original Sonic the Hedgehog games. This is consistent with the old ProSonic engine code, but because the new sprite format has animation data integrated into it, this is one less thing to program. I believe game designers will have a little easier time managing animations with this method.