I have a question..
when you say usability, do you mean that it should be fit for a game, and should be designed with animation in mind? Because it also says to not excede 48x48 and we could potentially squeeze in popeye which would allow much more detail, but doing so would take away from usability since then his range of motion would diminish..
Care to expand upon this Adam?
I may want to redo some sprites if It is better to pack as much popeye into the image as possible because then you can add more details since the popeye is as big as it can be.