diff --git a/imageapi/imageapi_imagemagick.module b/imageapi/imageapi_imagemagick.mod
index 4e6cf10..4afc657 100644
--- a/imageapi/imageapi_imagemagick.module
+++ b/imageapi/imageapi_imagemagick.module
@@ -217,7 +217,7 @@ function _imageapi_imagemagick_convert_exec($command_args, &$output, &$errors) {
       drupal_set_message(t('ImageMagick output: @output', array('@output' => $output)));
     }
 
-    if (!$return_code) {
+    if ($return_code !== 0) {
       // If ImageMagick returned a non-zero code, trigger a PHP error that will
       // be caught by Drupal's error handler, logged to the watchdog and
       // eventually displayed to the user if configured to do so.