I know when I did some game development with XNA they recommended that we try to group are sprites into fewer sheets because the graphic card could process it faster. Does this also apply to web based games?
Note: Not sure if this makes a difference but most of my artwork is pretty defined by separate levels. In other words I'm not really reusing artwork across levels, which kind of made me wonder if I should be loading sprites that never get used just for the sake of grouping them into a spritesheet.