Master - You have to upload your pictures onto a site like Photobucket, and link them from there.
After this site was "upgraded" a few months back, the admin imposed crazy restrictions on attaching photos. Unless you pictures are incredibly small, the function is totally useless.
The only way to post pictures now is to hyperlink them from elsewhere on the internet. Photobucket is a site that allows to to take a picture that is stored on your harddrive and host it on the internet. It's very easy to use...just go to
http://photobucket.com/ and sign up. Its really straight forward, but if you cant figure it out just let me know.
Hopefully that was of some help:)