Can I sell artwork for heads/parts? Is there a proper process to do it?
If so please tell me the algorithm.

I would also like to know whether copying my work, without buying it is punishable. If so how do I report that?

Thank you for your help.

Uh, you make them with artsy programs such as paint, photoshop, gimp etc.
Sizes are 128x128 px, 256x256 px, and 512x512 px.

Using your own work is not plagiarism. ;o
Using other people's work is only legal to a certain point.

To sell do I have to use "Safetrade" or something?
I saw somebody selling on forum and he was told not to and the thread was closed.

http://forum.toribash.com/showthread.php?t=418347

Those rules, where can I find them?

He tried to sell that texture in a part of the forum that is only meant to show the textures or other creative stuff such as videos, music, etc:
(http://forum.toribash.com/forumdisplay.php?f=14)

The correct subforum to sell or buy textures is this one:
(http://forum.toribash.com/forumdisplay.php?f=152)

Ah! that clears all my doubts. I thank you both.

Have a good day.