The hardest part about this is finding a place to store your pictures. There's nowhere on my forum you can upload pictures just like most other forums. I use myspace to upload but you can use photobucket as well. Let's assume you use photobucket
https://www.photobucket.comRegister for an account and then upload your pictures.
After your pictures are uploaded, there will be a list of things you can copy under the picture. Copy the URL.
Come here to the forum and in a new post there is a little Icon up top. If you put your mouse over it, it says image. Click it and paste the URL there. You can do this several times.
THe only problem with photobucket is it only lets you see the pictures so many times a day whereas myspace is infinate.