diff --git a/modules/libpr0n/src/imgRequest.cpp b/modules/libpr0n/src/imgRequest.cpp
index 099847eadb0..70ceee33029 100644
--- a/modules/libpr0n/src/imgRequest.cpp
+++ b/modules/libpr0n/src/imgRequest.cpp
@@ -36,6 +36,7 @@
 #include "nsICachingChannel.h"
 #include "nsILoadGroup.h"
 #include "nsIInputStream.h"
+#include "nsIMultiPartChannel.h"
 
 #include "nsIComponentManager.h"
 #include "nsIProxyObjectManager.h"
@@ -539,7 +540,11 @@ NS_IMETHODIMP imgRequest::OnStartRequest(nsIRequest *aRequest, nsISupports *ctxt
      open forever.
    */
   if (!mChannel) {
-    mChannel = do_QueryInterface(aRequest);
+    nsCOMPtr<nsIMultiPartChannel> mpchan(do_QueryInterface(aRequest));
+    if (mpchan)
+      mpchan->GetBaseChannel(getter_AddRefs(mChannel));
+    else
+      mChannel = do_QueryInterface(aRequest);
   }
 
   nsXPIDLCString mContentType;
@@ -588,6 +593,12 @@ NS_IMETHODIMP imgRequest::OnStartRequest(nsIRequest *aRequest, nsISupports *ctxt
     }
   }
 
+
+  // Shouldn't we be dead already if this gets hit?  Probably multipart/x-mixed-replace...
+  if (mObservers.Count() == 0) {
+    this->Cancel(NS_IMAGELIB_ERROR_FAILURE);
+  }
+
   return NS_OK;
 }
 
diff --git a/modules/libpr0n/src/imgRequestProxy.cpp b/modules/libpr0n/src/imgRequestProxy.cpp
index c5e144b430f..8a509a5d006 100644
--- a/modules/libpr0n/src/imgRequestProxy.cpp
+++ b/modules/libpr0n/src/imgRequestProxy.cpp
@@ -106,6 +106,7 @@ nsresult imgRequestProxy::Init(imgRequest *request, nsILoadGroup *aLoadGroup, im
         !(imageStatus & imgIRequest::STATUS_ERROR)) {
       aLoadGroup->AddRequest(this, cx);
       mLoadGroup = aLoadGroup;
+      mIsInLoadGroup = PR_TRUE;
     }
   }
 
@@ -361,6 +362,12 @@ void imgRequestProxy::OnStartRequest(nsIRequest *request, nsISupports *ctxt)
   GetName(getter_Copies(name));
   LOG_FUNC_WITH_PARAM(gImgLog, "imgRequestProxy::OnStartRequest", "name", NS_ConvertUCS2toUTF8(name).get());
 #endif
+
+  if (!mIsInLoadGroup && mLoadGroup) {
+    mLoadGroup->AddRequest(this, mContext);
+    mIsInLoadGroup = PR_TRUE;
+  }
+
 }
 
 void imgRequestProxy::OnStopRequest(nsIRequest *request, nsISupports *ctxt, nsresult statusCode)
@@ -383,6 +390,6 @@ void imgRequestProxy::OnStopRequest(nsIRequest *request, nsISupports *ctxt, nsre
   nsCOMPtr<imgIRequest> kungFuDeathGrip(this);
 
   mLoadGroup->RemoveRequest(this, mContext, statusCode);
-  mLoadGroup = nsnull;
+  mIsInLoadGroup = PR_FALSE;
 }
 
diff --git a/modules/libpr0n/src/imgRequestProxy.h b/modules/libpr0n/src/imgRequestProxy.h
index 7584244ae53..234803598c4 100644
--- a/modules/libpr0n/src/imgRequestProxy.h
+++ b/modules/libpr0n/src/imgRequestProxy.h
@@ -87,7 +87,8 @@ private:
   nsCOMPtr<nsILoadGroup> mLoadGroup;
 
   nsLoadFlags mLoadFlags;
-  PRBool mCanceled;
+  PRPackedBool mCanceled;
+  PRPackedBool mIsInLoadGroup;
 
   PRLock *mLock;
 };