went through this the other day myself. happy to help
you need to upload your pictures to a hosting site, like photobucket.
when youve done that, go to your album, and hover your cursor over the picture you want to put in the post on the BBS
there should be a number of codes/bunch of letters
you should see the IMG code.
clicking on that will automatically copy the code, then all you have to do is sign on to the BBS, and paste the code in the message box
tada!