what are the head texture sizes. i think i have a 512 but whats the difference in the sizes?
-----
and what is the differnece sizes?

128 256 512

You have a 128 head with a 512 art

the diffrence is that on a higher resolution texture deatils are more clearly and better to see.
means that if u got a 512x512 head texutre with a 512x512 headteuxre item u got the actual best possible quality of a toribash head.
a 128x128 head with a 128x128 texture doesnt looks that good and detailed.

actually there are 128, 256 and 512 size texture items. they probably wont release bigger ones. because it will prob get too big for some computers to handle.

The difference is the resolution. The higher the resolution (pixels) number, the more detailed is the head.