diff --git a/openlp/core/lib/imagemanager.py b/openlp/core/lib/imagemanager.py
index 10cfce616..b32e36194 100644
--- a/openlp/core/lib/imagemanager.py
+++ b/openlp/core/lib/imagemanager.py
@@ -100,7 +100,7 @@ class Image(object):
     variables ``image`` and ``image_bytes`` to ``None`` and add the image object
     to the queue of images to process.
     """
-    NUMBER = 0
+    secondary_priority = 0
     def __init__(self, name, path, source, background):
         self.name = name
         self.path = path
@@ -109,19 +109,20 @@ class Image(object):
         self.priority = Priority.Normal
         self.source = source
         self.background = background
-        self._number = Image.NUMBER
-        Image.NUMBER += 1
+        self.secondary_priority = Image.secondary_priority
+        Image.secondary_priority += 1
 
 
 class PriorityQueue(Queue.PriorityQueue):
     """
     Customised ``Queue.PriorityQueue``.
 
-    Each item in the queue must be tuple with three values. The fist value
-    is the priority, the second value the image's ``_number`` attribute. The
-    last value the :class:`Image` instance itself::
+    Each item in the queue must be tuple with three values. The first value
+    is the :class:`Image`'s ``priority`` attribute, the second value
+    the :class:`Image`'s ``secondary_priority`` attribute. The last value the
+    :class:`Image` instance itself::
 
-        (Priority.Normal, image._number, image)
+        (image.priority, image.secondary_priority, image)
 
     Doing this, the :class:`Queue.PriorityQueue` will sort the images according
     to their priorities, but also according to there number. However, the number
@@ -141,7 +142,7 @@ class PriorityQueue(Queue.PriorityQueue):
         """
         self.remove(image)
         image.priority = new_priority
-        self.put((image.priority, image._number, image))
+        self.put((image.priority, image.secondary_priority, image))
 
     def remove(self, image):
         """
@@ -150,8 +151,8 @@ class PriorityQueue(Queue.PriorityQueue):
         ``image``
             The image to remove. This should be an ``Image`` instance.
         """
-        if (image.priority, image._number, image) in self.queue:
-            self.queue.remove((image.priority, image._number, image))
+        if (image.priority, image.secondary_priority, image) in self.queue:
+            self.queue.remove((image.priority, image.secondary_priority, image))
 
 
 class ImageManager(QtCore.QObject):
@@ -276,7 +277,8 @@ class ImageManager(QtCore.QObject):
         if not name in self._cache:
             image = Image(name, path, source, background)
             self._cache[name] = image
-            self._conversion_queue.put((image.priority, image._number, image))
+            self._conversion_queue.put(
+                (image.priority, image.secondary_priority, image))
         else:
             log.debug(u'Image in cache %s:%s' % (name, path))
         # We want only one thread.