diff --git a/testing/image_diff/image_diff.cpp b/testing/image_diff/image_diff.cpp
index 3da138b..f988e71 100644
--- a/testing/image_diff/image_diff.cpp
+++ b/testing/image_diff/image_diff.cpp
@@ -63,8 +63,7 @@
 
     fclose(f);
 
-    data_ = image_diff_png::DecodePNG(compressed.data(), compressed.size(), &w_,
-                                      &h_);
+    data_ = image_diff_png::DecodePNG(compressed, &w_, &h_);
     if (data_.empty()) {
       Clear();
       return false;
diff --git a/testing/image_diff/image_diff_png.cpp b/testing/image_diff/image_diff_png.cpp
index ef9d4aa..eec8a04 100644
--- a/testing/image_diff/image_diff_png.cpp
+++ b/testing/image_diff/image_diff_png.cpp
@@ -659,11 +659,10 @@
 
 }  // namespace
 
-std::vector<unsigned char> DecodePNG(const unsigned char* input,
-                                     size_t input_size,
+std::vector<unsigned char> DecodePNG(pdfium::span<const unsigned char> input,
                                      int* width,
                                      int* height) {
-  return Decode(input, input_size, FORMAT_RGBA, width, height);
+  return Decode(input.data(), input.size(), FORMAT_RGBA, width, height);
 }
 
 std::vector<unsigned char> EncodeBGRPNG(const unsigned char* input,
diff --git a/testing/image_diff/image_diff_png.h b/testing/image_diff/image_diff_png.h
index 380e6dc..3afbd6a 100644
--- a/testing/image_diff/image_diff_png.h
+++ b/testing/image_diff/image_diff_png.h
@@ -9,11 +9,12 @@
 
 #include <vector>
 
+#include "third_party/base/span.h"
+
 namespace image_diff_png {
 
 // Decode a PNG into an RGBA pixel array.
-std::vector<unsigned char> DecodePNG(const unsigned char* input,
-                                     size_t input_size,
+std::vector<unsigned char> DecodePNG(pdfium::span<const unsigned char> input,
                                      int* width,
                                      int* height);