imagecreatefrompng() returns an image identifier representing the image obtained from the given filename.
imagecreatefrompng() returns an empty string on failure. It also outputs an error message, which unfortunately displays as a broken link in a browser. To ease debugging the following example will produce an error PNG:
Example 1. Example to handle an error during creation (courtesy vic at zymsys dot com)
Tip: You can use a URL as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename and Appendix I for a list of supported URL protocols.
Windows versions of PHP prior to PHP 4.3.0 do not support accessing remote files via this function, even if allow_url_fopen is enabled.