For PHP drawing, you must first confirm whether the gd library is enabled. Go to the php.ini file, find extension=php_gd2.dll, remove the previous ";" and restart the server.
If the normal image is still not displayed in the drawing, it means that the image information is incorrect when the server responds to the request. Make sure there is nothing in front of , including html.
In addition, the picture is not output yet. Before drawing, clear the cache (that is, before writing the header). Write ob_clean(); You also need to clear the cache when the file is not open).