diff --git a/image/src/RasterImage.cpp b/image/src/RasterImage.cpp
index b2e88bc9295e..19cca9bd4a94 100644
--- a/image/src/RasterImage.cpp
+++ b/image/src/RasterImage.cpp
@@ -3278,7 +3278,6 @@ RasterImage::IsDecodeFinished()
   // Precondition
   mDecodingMutex.AssertCurrentThreadOwns();
   NS_ABORT_IF_FALSE(mDecoder, "Can't call IsDecodeFinished() without decoder!");
-  MOZ_ASSERT(mDecodeRequest);
 
   // The decode is complete if we got what we wanted.
   if (mDecoder->IsSizeDecode()) {
@@ -3288,11 +3287,12 @@ RasterImage::IsDecodeFinished()
   } else if (mDecoder->GetDecodeDone()) {
     return true;
   }
-  
+
   // If the decoder returned because it needed a new frame and we haven't
   // written to it since then, the decoder may be storing data that it hasn't
   // decoded yet.
-  if (mDecoder->NeedsNewFrame() || mDecodeRequest->mAllocatedNewFrame) {
+  if (mDecoder->NeedsNewFrame() ||
+      (mDecodeRequest && mDecodeRequest->mAllocatedNewFrame)) {
     return false;
   }