diff --git a/testing/image_diff/image_diff.cpp b/testing/image_diff/image_diff.cpp
index 00116c7..f9d70f3 100644
--- a/testing/image_diff/image_diff.cpp
+++ b/testing/image_diff/image_diff.cpp
@@ -279,9 +279,11 @@
     return kStatusSame;
 
   std::vector<unsigned char> png_encoding;
-  image_diff_png::EncodeRGBAPNG(diff_image.data(), diff_image.w(),
-                                diff_image.h(), diff_image.w() * 4,
-                                &png_encoding);
+  if (!image_diff_png::EncodeRGBAPNG(diff_image.data(), diff_image.w(),
+                                     diff_image.h(), diff_image.w() * 4,
+                                     &png_encoding)) {
+    return kStatusError;
+  }
 
   FILE* f = fopen(out_file.c_str(), "wb");
   if (!f)