diff --git a/imagemagick.module b/imagemagick.module
index 804338f..c296183 100644
--- a/imagemagick.module
+++ b/imagemagick.module
@@ -373,6 +373,11 @@ function _imagemagick_convert($source, $destination, $args) {
 
   $source = drupal_realpath($source);
   $destination = drupal_realpath($destination);
+
+  if (!$source || !$destination) {
+    return FALSE;
+  }
+
   $destination_format = '';
 
   $args['quality'] = '-quality ' . escapeshellarg(variable_get('imagemagick_quality', 75));