diff --git a/src/thumbnail.js b/src/thumbnail.js
index d814804..bb41c93 100644
--- a/src/thumbnail.js
+++ b/src/thumbnail.js
@@ -62,6 +62,8 @@ createQueue = function(settings) {
           im.resize(task.options, function(err, stdout, stderr) {
             callback();
           });
+        } else {
+          callback();
         }
 
       });
@@ -78,6 +80,8 @@ createQueue = function(settings) {
         im.resize(task.options, function(err, stdout, stderr) {
           callback();
         });
+      } else {
+        callback();
       }
     }