[kh99]

Your widget code needs to set $output to the html for your widget instead of using ?> and <?php or echo. Try this:

$dir = "user-uploads-thumbnails/";
$images = scandir($dir);
$i = rand(1, sizeof($images)-5);

$output = '<a> <a href="user-uploads/' . $images[$i] . '">
<img src="user-uploads-thumbnails/' . $images[$i] . '" alt="" /> <a/>';