diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 7adf720b389d..78e8bbf0e6e6 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -4124,7 +4124,7 @@ nsDocument::LookupImageElement(const nsAString& aId)
   if (aId.IsEmpty())
     return nsnull;
 
-  nsIdentifierMapEntry *entry = mIdentifierMap.PutEntry(aId);
+  nsIdentifierMapEntry *entry = mIdentifierMap.GetEntry(aId);
   return entry ? entry->GetImageIdElement() : nsnull;
 }