<?php
Header("Content-type: image/jpeg");
//create a new image
$image = ImageCreate(200,200);
//create white (for background )
$white = ImageColorAllocate($image ,255,255,255);
//create blue for text
$blue = ImageColorAllocate($image , 0,0,255);
//OK lets create our white background
ImageFilledRectangle($image ,0,0,200,200,$white);
//display some text
ImageString($image,10,15,10,'iain@iain.com',$blue);
//output image to browser as a JPEG
ImageJPEG($image);
//clean up by destroying the image
ImageDestroy($image);
?>

NOw include this on your page like this

<img src="gdemail.php">