diff --git a/webrender/src/render_backend.rs b/webrender/src/render_backend.rs
index d8a13c879b..e18468891b 100644
--- a/webrender/src/render_backend.rs
+++ b/webrender/src/render_backend.rs
@@ -1110,10 +1110,10 @@ impl RenderBackend {
             txn.blob_rasterizer = blob_rasterizer;
         }
 
-        if !transaction_msg.use_scene_builder_thread && txn.can_skip_scene_builder() {
-            if let Some(rasterizer) = txn.blob_rasterizer.take() {
-                self.resource_cache.set_blob_rasterizer(rasterizer);
-            }
+        if !transaction_msg.use_scene_builder_thread &&
+            txn.can_skip_scene_builder() &&
+            txn.blob_rasterizer.is_none() {
+
             self.update_document(
                 txn.document_id,
                 replace(&mut txn.resource_updates, Vec::new()),
diff --git a/webrender/src/resource_cache.rs b/webrender/src/resource_cache.rs
index 95c712602a..64be2ddf9d 100644
--- a/webrender/src/resource_cache.rs
+++ b/webrender/src/resource_cache.rs
@@ -1082,7 +1082,7 @@ impl ResourceCache {
         &mut self,
         keys: &[BlobImageKey]
     ) -> (Option<Box<AsyncBlobImageRasterizer>>, Vec<BlobImageParams>) {
-        if self.blob_image_handler.is_none() {
+        if self.blob_image_handler.is_none() || keys.is_empty() {
             return (None, Vec::new());
         }