This is an example of using a date to create an actual PNG graphic image.

This is using today's date (default, no variable given in URL):
Calendar

This is using a specified date in this format: 02/11/2008
Calendar

View the HTML source to see how the calendar is displayed.

These are the required files used in the script:
The Calendar PNG Image
Arial True-Type Font
Arial Bold True-Type Font

This is the actual PHP script:

<?php 
// Calendar Day Cell - Generator 

// Get Date from link in the form of mm/dd/yyyy 
$date = $_GET['d']; 

// If a date is provided, convert to the proper format 
if($date) 
{ 
list($month, $day, $year) = explode('/', $date); 
if(checkdate($month, $day, $year)) 
list($month, $day, $year) = explode('/', date('F/jS/Y', mktime(0, 0, 0, $month, $day, $year))); 
else 
list($month, $day, $year) = explode('/', date('F/jS/Y')); 
} 
else 
{ 
list($month, $day, $year) = explode('/', date('F/jS/Y')); 
} 

// Generate Image & set width 
$image = imagecreatefrompng("calendar.png"); 
$imageWidth = imagesx($image); 

// Generate Month 
$color = imagecolorallocate($image, 255, 255, 255); 
$font = "arialbd.ttf"; 
$fontSize = "8"; 
$ret = imagettfbbox($fontSize, 0, $font, $month); 
imagettftext($image, $fontSize, 0, ($imageWidth - $ret[2]) / 2, 12, $color, $font, $month); 

// Generate Day 
$color = imagecolorallocate($image, 0, 0, 0); 
$font = "arial.ttf"; 
$fontSize = "14"; 
$ret = imagettfbbox($fontSize, 0, $font, $day); 
imagettftext($image, $fontSize, 0, ($imageWidth - $ret[2]) / 2, 38, $color, $font, $day); 

// Generate Year 
$color = imagecolorallocate($image, 0, 0, 0); 
$font = "arial.ttf"; 
$fontSize = "10"; 
$ret = imagettfbbox($fontSize, 0, $font, $year); 
imagettftext($image, $fontSize, 0, ($imageWidth - $ret[2]) / 2, 56, $color, $font, $year); 

// Output & Free Memory 
header("Content-type: image/png"); 
imagepng($image); 
imagedestroy($image); 
?>