Send XHTML emails with images

Hi, I've made an XHTML page to be send as a rich e-mail so I can do more as just tekst. Everything is fine, except for the images. In the source code I say the images are like <img src="http://www.domain.com/pic.jpg" alt="" /> but wen I send the email, I can't see the images in Outlook Express or Hotmail (in browser). Here's my testing script: <?php $subject = "onderwerp"; $message = ' Message body (XHTML) '; $headers = "MIME-Version: 1.0\r\n"; $headers .= "Content-type: text/html; charset=iso-8859-1\r\n"; $headers .= "From: GeryDuyck <geryduyck@gmail.com>\r\n"; $email = $_GET['mail']; mail($email, $subject, $message, $headers); ?> I dunno what I oversaw, maybe a missing header or something, or maybe I need to embed the images with the e-mail in stead of opening them from somewhere else on the web. Anyway, either way's I don't know how to do, so all hint's/tips are welcome! Gery