There should already be a column in the cats mysql table for storing the cat image, so first of all make sure those are all setup properly. What id do is set these to stuff like dvdr.gif, xvid,gif, music.gif .. then store all the caticons in a folder called "caticons" in the pic or images directory.
then in bittorrent.php inside the genrelist() function add "image" to the category select fields in the mysql query so it will fetch those images u should have set in the table.
then its simply a case of looping through on the browse page, so for your select list you may wanna use
Code:
foreach ($cats as $cat)
echo "<option value='".$cat['id']."'>".$cat['name']."</option>";
and for a list of images
Code:
foreach ($cats as $cat)
echo "<img src='images/caticons/".$cat['image']."' border='0' alt='".$cat['name']."' />";