<img> tag not transferring to PHP

I have a CKEditor page. I want the users to be able to create HTML documents and email them to recipients using PHP. Text, forms, and other HTML stuff gets picked up by the PHP $_POST[''] variable except for the <img> tag. I don't know why, but when I try to insert an image into CKEditor it shows up, but then when I grab the source and mail it the image is not there.

thanks,
mike