anyone knoes how to add a picture to these messages??
i tried the [img]http://image_url[/img] thing and it didn't show the picture...

It looks like you have the right right protocol. My suggestion would be to upload your image to a free hosting service like image shack.com.
Then when after you have submitted it for the upload, they will give you several possibilities to link to Bb's etc. Choose theURL that says "direct link to image and
copy it. The on PSC forum site, for example, put the following syntax:

[img]paste URL you just copied[/img]

I have done it many times with this protocol, and it has never failed to work.
Good luck..