Include image of a category

[unnpro]

Hi,
how can I include an image in a category only if it exits on the server?

Something like:

PHP Code:

ob_start();

if (file_exists("images/categories/cat_".$forumid.".jpg")) {
    $includeimgcat = "<img src=\"images/categories/cat_".$forumid.".jpg\" width=\"85\" height=\"85\" alt=\"\" style=\"vertical-align: middle;\" />";
} else {
    $includeimgcat = "";
}

ob_end_clean(); 


I tried to write a plugin and edit forumhome_forumbit_level1_nopost template without any result

TIA