--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -3348,24 +3348,21 @@ struct nsCursorImage
   bool mHaveHotspot;
   float mHotspotX, mHotspotY;
 
   nsCursorImage();
   nsCursorImage(const nsCursorImage& aOther);
   ~nsCursorImage();
 
   nsCursorImage& operator=(const nsCursorImage& aOther);
-  /*
-   * We hide mImage and force access through the getter and setter so that we
-   * can lock the images we use. Cursor images are likely to be small, so we
-   * don't care about discarding them. See bug 512260.
-   * */
+
   void SetImage(imgIRequest *aImage) {
     if (mImage) {
       mImage->UnlockImage();
+      mImage->RequestDiscard();
     }
     mImage = aImage;
     if (mImage) {
       mImage->LockImage();
     }
   }
   imgIRequest* GetImage() const {
     return mImage;