Only admins and moderators can attach an image to a post.
We have this restirction so people do not load porn and other stuff onto our server.
Everyone else needs to link or insert an image located on a web server.
Most photo post websites will not allow you to hot link an image
from their web server to another website or message board.
They do this to save their bandwidth.
To insert and image into a post...
Click on the insert image icon "yellow box with image in" and type in the URL or address of the image you want to insert.
It will look something like "http://www.website.com/image.jpg"