I am in process of getting an upgrade to the photo storage capacity which is presently at its limit of 500mb, it is in hand with the server, in meantime you may not be able to upload photos (I can't!).
Martin, below the message panel you will see a tab 'upload attachment', use that then 'browse' and 'add the file'. For best result, then put the cursor below your message and press 'place in line' Then submit.