Hi,
To insert pictures, you will need to host them externally, RME does not provide web space for anything besides small avatars. flickr and photobucket are popular choices. After getting the link, you can use the BBCode capability in this forum software to embed the picture in a post. It looks something like this:
[img]http://www.some_photo_url.com/path[/img]
For other files, you will need to provide your own web space or use a service to host the files. Yousendit and senduit are popular services. After uploading the file you can post the hyperlink for download. Be aware that people may not be interested in clicking a blind link, since they cannot be certain of what they might download.
Also, there are links directly below the post/reply text field explaining BBCode, the IMG tag and smilies. And the buttons above the text field make it very easy to use these formatting methods without having to understand any of it.
Regards,
Jeff Petersen
Synthax Inc.