[vibrunazo]

That only explains why use a sprite sheet. But not why use jpg instead of gif. Neither it talks about the alternative of gif animation. Does the javascript dom method really offers better performance than a simple gif animation? Or were gif animations taken off the equation before that comparison for other reasons?

[robterrell]

Animated GIFs max out at 8 bits of color (per frame, but still). The animation cycle of GIFs starts when the image is loaded and can't be controlled via JS. Yes, if you just wanted an 8-bit orb bouncing, it's a fine choice. For a game sprite, it's less so.