Bright Forest Theme Guidance In Need

[SPOTFIN]

I am very new to this so any help (specific direction) would be greatly appreciated. Bright Forest is the theme in use (matherfishforum.com) on the left of each category is a pic of the BF theme, I am trying to change that picture out, it will also dim when category is not with posts, so not sure if I am looking to change more than 1 pic or setting and cannot figure out how to do it. Any help would be greatly appreciated.  P.S I have never used CPanel before ! host is lolohosting if it makes any difference.
thank you

[Shambles]

Here's the proper support thread:

http://www.simplemachines.org/community/index.php?topic=187247.0

(PS, no need to use all caps in your title)

[SPOTFIN]

thank you, I will move the post