--- a/image/src/imgRequestProxy.cpp
+++ b/image/src/imgRequestProxy.cpp
@@ -50,17 +50,22 @@ class RequestBehaviour : public ProxyBeh
   virtual imgStatusTracker& GetStatusTracker() const MOZ_OVERRIDE;
 
   virtual imgRequest* GetOwner() const MOZ_OVERRIDE {
     return mOwner;
   }
 
   virtual void SetOwner(imgRequest* aOwner) MOZ_OVERRIDE {
     mOwner = aOwner;
-    mOwnerHasImage = !!aOwner->GetStatusTracker().GetImage();
+
+    if (mOwner) {
+      mOwnerHasImage = !!aOwner->GetStatusTracker().GetImage();
+    } else {
+      mOwnerHasImage = false;
+    }
   }
 
  private:
   // We maintain the following invariant:
   // The proxy is registered at most with a single imgRequest as an observer,
   // and whenever it is, mOwner points to that object. This helps ensure that
   // imgRequestProxy::~imgRequestProxy unregisters the proxy as an observer
   // from whatever request it was registered with (if any). This, in turn,