--- libpng-1.2.6beta2/pngerror.c.orig     Thu Oct  3 15:32:27 2002
+++ libpng-1.2.6beta2/pngerror.c  Wed May  5 01:01:13 CEST 2004
@@ -135,10 +135,14 @@
       buffer[iout] = 0;
    else
    {
+      int len = strlen(error_message);
+
+      if (len > 63)
+        len = 63;
       buffer[iout++] = ':';
       buffer[iout++] = ' ';
-      png_memcpy(buffer+iout, error_message, 64);
-      buffer[iout+63] = 0;
+      png_memcpy(buffer+iout, error_message, len);
+      buffer[iout+len] = 0;
    }
 }