(PHP 3 >= 3.0.13, PHP 4, PHP 5)
The imagepng() outputs a GD image stream (image) in PNG format to standard output (usually the browser) or, if a filename is given by the filename it outputs the image to the file.
<?php$im = imagecreatefrompng("test.png");imagepng($im);?>
See also imagegif(), imagewbmp(), imagejpeg(), imagetypes().