Welcome to JD, Swede. Good to have some more European influence around here (I'm presuming). Definitely a fun place to discuss the hobby, and quite different from RS. As for a test forum, we don't have one. But feel free to test some things out right here in this thread if you'd like, and if they don't work, just do an edit back over your post and try again 'til you can figure it out. We can always delete your post later on if you'd like, once you've got the hang of things, no problem.
As for posting pix, check out this thread: Posting pictures.
Good luck, and holler if you've got any other questions! Looking forward to chatting with you around the boards here...