diff --git a/src/image.cpp b/src/image.cpp
index 2516ae3fdc..5caaf350dd 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -1122,7 +1122,7 @@ void Image::write_PNG(FILE *fp)
   }
 
   png_init_io(png_ptr, fp);
-  png_set_compression_level(png_ptr,Z_BEST_COMPRESSION);
+  png_set_compression_level(png_ptr,Z_BEST_SPEED);
   png_set_IHDR(png_ptr,info_ptr,width/aafactor,height/aafactor,8,PNG_COLOR_TYPE_RGB,
     PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);