Use a service such as imageshack, located at www.imageshack.us and upload your photos there, then on the upload results page scroll down to the very bottom of the page and choose the url to your image that Imageshack says "NOT" to use, highlight it, and copy it.
Then in your message here, simply click the icon in the reply tools of your message (the one that looks like a tree, it's two to the left of the happyface icons, and enter the url in the url field, then confirm it and your image will show up in your message post:
