diff --git a/gfx/src/shared/gfxImageFrame.cpp b/gfx/src/shared/gfxImageFrame.cpp
index 89e7831702b7..75819b6be151 100644
--- a/gfx/src/shared/gfxImageFrame.cpp
+++ b/gfx/src/shared/gfxImageFrame.cpp
@@ -348,7 +348,10 @@ NS_IMETHODIMP gfxImageFrame::GetTimeout(PRInt32 *aTimeout)
   if (!mInitalized)
     return NS_ERROR_NOT_INITIALIZED;
 
-  *aTimeout = mTimeout;
+  if (mTimeout == 0)
+    *aTimeout = 100; // Ensure a minimal time between updates so we don't throttle the UI thread.
+  else
+    *aTimeout = mTimeout;
   return NS_OK;
 }
 
diff --git a/gfx2/src/gfxImageFrame.cpp b/gfx2/src/gfxImageFrame.cpp
index 89e7831702b7..75819b6be151 100644
--- a/gfx2/src/gfxImageFrame.cpp
+++ b/gfx2/src/gfxImageFrame.cpp
@@ -348,7 +348,10 @@ NS_IMETHODIMP gfxImageFrame::GetTimeout(PRInt32 *aTimeout)
   if (!mInitalized)
     return NS_ERROR_NOT_INITIALIZED;
 
-  *aTimeout = mTimeout;
+  if (mTimeout == 0)
+    *aTimeout = 100; // Ensure a minimal time between updates so we don't throttle the UI thread.
+  else
+    *aTimeout = mTimeout;
   return NS_OK;
 }
 
diff --git a/modules/libpr0n/src/imgContainer.cpp b/modules/libpr0n/src/imgContainer.cpp
index 2170dc64e1f7..5fc00cc767b1 100644
--- a/modules/libpr0n/src/imgContainer.cpp
+++ b/modules/libpr0n/src/imgContainer.cpp
@@ -174,8 +174,7 @@ NS_IMETHODIMP imgContainer::AppendFrame(gfxIImageFrame *item)
       nsCOMPtr<gfxIImageFrame> currentFrame;
       this->GetFrameAt(mCurrentDecodingFrameIndex, getter_AddRefs(currentFrame));
       currentFrame->GetTimeout(&timeout);
-      if (timeout != -1 &&
-         timeout >= 0) { // -1 means display this frame forever
+      if (timeout > 0) { // -1 means display this frame forever
         
         if(mAnimating) {
           // Since we have more than one frame we need a timer
@@ -216,8 +215,7 @@ NS_IMETHODIMP imgContainer::EndFrameDecode(PRUint32 aFrameNum, PRUint32 aTimeout
     PRUint32 numFrames;
     this->GetNumFrames(&numFrames);
     if (numFrames > 1) {
-        if (aTimeout != -1 &&
-            aTimeout >= 0) { // -1 means display this frame forever
+        if (aTimeout > 0) { // -1 means display this frame forever
 
           mAnimating = PR_TRUE;
           mTimer = do_CreateInstance("@mozilla.org/timer;1");
@@ -269,8 +267,7 @@ NS_IMETHODIMP imgContainer::StartAnimation()
     this->GetCurrentFrame(getter_AddRefs(currentFrame));
     if (currentFrame) {
       currentFrame->GetTimeout(&timeout);
-      if (timeout != -1 &&
-          timeout >= 0) { // -1 means display this frame forever
+      if (timeout > 0) { // -1 means display this frame forever
 
         mAnimating = PR_TRUE;
         if(!mTimer) mTimer = do_CreateInstance("@mozilla.org/timer;1");
@@ -381,7 +378,7 @@ NS_IMETHODIMP_(void) imgContainer::Notify(nsITimer *timer)
     if(!nextFrame) return;
   }
 
-  if(timeout >= 0)
+  if(timeout > 0)
     mTimer->SetDelay(timeout);
   else
     this->StopAnimation();