just a crosslink to the thread where i pasted code in order to use images instead of regular text as categories in the categories box..
http://www.oscommerce.com/forums/viewtopic.php?t=44676
still lacks tests for filename-correctness but should work for 99% of all cases
basic concept: categories-name has to match filename with .jpg for currently selected language, if image is missing, then the script detects this and falls back to regular textlink