You first have to upload your pictures to a web server. If your internet account comes with web server space (most do) then use that. Or you can use a picture album site like Photobucket.com. Either way, once your picture is uploaded, and you can type a URL into your browser that causes the picture to display, then you copy that URL into the "Image URL" block directly above the block where you type your message. Pretty simple?
Tom
Tom