- $tw = (isset($j->thumbnail_width)) ? $j->thumbnail_width:200;
- $th = (isset($j->thumbnail_height)) ? $j->thumbnail_height:180;
- $tr = $tw/$th;
+ $tw = (isset($j->thumbnail_width) && intval($j->thumbnail_width)) ? $j->thumbnail_width:200;
+ $th = (isset($j->thumbnail_height) && intval($j->thumbnail_height)) ? $j->thumbnail_height:180;
+ // make sure we don't attempt divide by zero, fallback is a 1:1 ratio
+ $tr = (($th) ? $tw/$th : 1);