You can absolutely attach pictures, as seen in the recent "dear campers" story update. You just write " img][/img] " (though i removed one bracket for show an tell) and copy the image address in the middle, or click the helpful "insert image" button. I don't know if you can adjust the size of the pictures though. Example below.
You can post links to other sites, at least it is currently being done. Usually in the signature at the bottom of your posts.