--- pngimage.c
+++ pngimage.c
@@ -41,7 +41,7 @@
   rewind (png_file);
   if (fread (sigbytes, 1, sizeof(sigbytes), png_file) !=
       sizeof(sigbytes) ||
-      (!png_check_sig (sigbytes, sizeof(sigbytes))))
+      (png_sig_cmp (sigbytes, 0, sizeof(sigbytes))))
     return 0;
   else
     return 1;
--- thumbnail.c
+++ thumbnail.c
@@ -78,7 +78,7 @@
   }
   if (fread (sigbytes, 1, sizeof(sigbytes), thumb_file) !=
       sizeof(sigbytes) ||
-      (!png_check_sig (sigbytes, sizeof(sigbytes)))) {
+      (png_sig_cmp (sigbytes, 0, sizeof(sigbytes)))) {
     fprintf (stderr, "\nThumbnail not a png file! Skipping\n");
     return NULL;
   }