How do I add new types of star graphics for certain groups?

[Storman™]

The images must go in the {theme URL}/images/  folder for your theme (no where else).

Then edit the membergroup by going to:

Administration Center => Membergroups => Edit Membergroups

Find the group in question and click on "Modify". Then scroll down and add the file name into the "Star image filename:" field

[Zelix]

The images must go in the {theme URL}/images/  folder for your theme (no where else).

ok, my theme folder in desktop and i have into forums. How i edit or add image into forums ?

[Storman™]

Sorry, I don't understand what you mean ? 

[Arantor]

You use FTP to upload images, see How do I use FTP? / What is FTP?