diff --git a/content/base/src/nsDataDocumentContentPolicy.cpp b/content/base/src/nsDataDocumentContentPolicy.cpp
index 4f198cfe6a64..f9da09b4202c 100644
--- a/content/base/src/nsDataDocumentContentPolicy.cpp
+++ b/content/base/src/nsDataDocumentContentPolicy.cpp
@@ -78,8 +78,8 @@ nsDataDocumentContentPolicy::ShouldLoad(PRUint32 aContentType,
     return NS_OK;
   }
 
-  // Nothing else is OK to load for data documents
-  if (doc->IsLoadedAsData()) {
+  // Nothing else is OK to load for data documents or SVG-as-an-image documents
+  if (doc->IsLoadedAsData() || doc->IsBeingUsedAsImage()) {
     *aDecision = nsIContentPolicy::REJECT_TYPE;
     return NS_OK;
   }
diff --git a/layout/reftests/svg/as-image/img-and-image-1-ref.svg b/layout/reftests/svg/as-image/img-and-image-1-ref.svg
index 275ed35ea634..022a907aadbb 100644
--- a/layout/reftests/svg/as-image/img-and-image-1-ref.svg
+++ b/layout/reftests/svg/as-image/img-and-image-1-ref.svg
@@ -29,10 +29,18 @@
     <!-- Single column from the testcase -->
     <g id="column">
       <use y="0"   xlink:href="#pAR_xMaxYMax_slice" width="60"  height="20"/>
+<!--
+      XXXdholbert As of bug 628747, the svg:image elements *within* an SVG
+      image are no longer honored, so I'm commenting out the chunk of this
+      reference case that was expected to match those parts of the testcase.
+      We might eventually want to just remove this chunk, but I'm leaving it
+      for now in case we refine this behavior later on.
+
       <use y="50"  xlink:href="#pAR_xMinYMin_slice" width="100" height="40"/>
       <use y="100" xlink:href="#pAR_none"           width="100" height="40"/>
       <use y="150" xlink:href="#pAR_xMaxYMax_meet"  width="80"  height="40"/>
       <use y="200" xlink:href="#pAR_xMaxYMax_slice" width="80"  height="40"/>
+-->
       <use y="250" xlink:href="#pAR_xMaxYMax_slice" width="30"  height="50"/>
     </g>
   </defs>
diff --git a/layout/reftests/svg/as-image/reftest.list b/layout/reftests/svg/as-image/reftest.list
index 2eb5cb18efd6..b554c8f3ad99 100644
--- a/layout/reftests/svg/as-image/reftest.list
+++ b/layout/reftests/svg/as-image/reftest.list
@@ -52,8 +52,8 @@ fails == canvas-drawImage-slice-1b.html lime100x100-ref.html # XXX all edges fuz
 
 # Test with mix of <html:img> and <svg:image> referring to the same images,
 # with a variety of preserveAspectRatio values in play.
-# NOTE: The reference cases in this test triggers 72 assertions (bug 563481)
-asserts(72) == img-and-image-1.html img-and-image-1-ref.svg
+# NOTE: The reference cases in this test triggers 30 assertions (bug 563481)
+asserts(30) == img-and-image-1.html img-and-image-1-ref.svg
  
 # More complex <img> tests
 random-if(gtk2Widget) == img-anim-1.html  lime100x100-ref.html # bug 612214