How can i post a picture an make it immediately visible?

example: http://www.peachyforum.com/forums/36621/ShowPost.aspx

p.s. if i copy and paste the pic, it is not visible

Best and easiest way is using a free imagehost like eg.:

http://www.imagevenue.com

After uploading your pic with them they provide you with several links and several options for posting.

Just try it.  It's a simple, easy and free service.