If I understand correctly...

The php script works fine and you received the newsletter.
The newsletter is formatted properly with the HTML.

The problem is that the pictures aren't appearing when you read the newsletter in your e-mail.

If that's the case, then you're problem may be in the way you specify the source for your images. In the HTML, you've got a reference to one image as: "images/newsletter_01.gif"

This type of relative URL won't work in an e-mail. The browser is looking for the file "images/newsletter_01.gif" inside the folder that the e-mail script is executing.

If you replace all of your relative URLs for images with absolute URLs (i.e. "http://www.mydomain.com/images/newsletter_01.gif"), they should appear correctly.

If that's not the problem, also make sure that your e-mail reader isn't blocking the images. I know that gmail blocks images by default. Some other web-based e-mail readers probably do the same thing.

Good luck,
- Walkere