The following code does not work with php4.0.3p1 under windows NT.
It shows complete garbage text on the display.
However if you save the image to a png file and use <img src=$filename> tag it will work.

<?php
Header("Content-Type: image/png");
$im = ImageCreate(100,100);
$black = ImageColorAllocate($im,0,0,0);
$white = ImageColorAllocate($im,255,255,255);

ImageLine($im,0,0,99,99,$white);


if(ImageTypes() & IMG_PNG) {echo "PNG SUPPORTED";}
if(ImageTypes() & IMG_GIF) {echo "GIF SUPPORTED";}
ImagePng($im);
ImageDestroy($im);
?>