diff --git a/ChangeLog b/ChangeLog
index 3700e37aa..82f99dbeb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-09-08  Eric Wasylishen  <ewasylishen@gmail.com>
+
+	* Source/NSImage.m: Throw an exception if you attempt to lock focus on an image with
+	size (0, 0)
+	* Source/NSCachedImageRep.m: Throw an exception if you attempt to create a cached
+	image rep with a size of (0, 0).
+
 2011-09-07  Eric Wasylishen  <ewasylishen@gmail.com>
 
 	* Source/NSFontPanel.m: Add a tooltip on the character panel button
diff --git a/Source/NSCachedImageRep.m b/Source/NSCachedImageRep.m
index 444e51609..6f03301c2 100644
--- a/Source/NSCachedImageRep.m
+++ b/Source/NSCachedImageRep.m
@@ -89,6 +89,14 @@
 {
   NSWindow	*win;
 
+  if (aSize.width <= 0 || aSize.height <= 0 ||
+      pixelsWide <= 0 || pixelsHigh <= 0)
+    {
+      [NSException raise: NSInvalidArgumentException
+		  format: @"NSCachedImageRep created with size %@ pixelsWide %d pixelsHigh %d",
+		   NSStringFromSize(aSize), pixelsWide, pixelsHigh];
+    }
+
   // FIXME: Only create new window when separate is YES
   win = [[GSCacheW alloc] initWithContentRect: NSMakeRect(0, 0, pixelsWide, pixelsHigh)
 				    styleMask: NSBorderlessWindowMask | NSUnscaledWindowMask
diff --git a/Source/NSImage.m b/Source/NSImage.m
index 33f191fc8..3277f8dd1 100644
--- a/Source/NSImage.m
+++ b/Source/NSImage.m
@@ -1055,6 +1055,10 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
       NSWindow *window;
       GSRepData *repd;
 
+      if (NSSizesEqual(NSZeroSize, [self size]))
+        [NSException raise: NSImageCacheException
+                     format: @"Cannot lock focus on image with size (0, 0)"];
+
       if (imageRep == nil)
         imageRep = [self bestRepresentationForDevice: nil];