ozzy47, I think you did not understand what I wanted, but I think I was not clear enough.
Well, I tried to create a 35 x 35 px icon for the read and unread forums, but it is automatically resized and it does not have the initial dimension anymore (it is smaller). I guess I have to edit the default size in a file and my question is: what file do I need to modify and where?
I hope I was clearer now.
Thanks in advance!
Solved- thanks anyway!