Basically first you would need to host your images somewhere like ie: imageshack.
When an image is uploaded it will give you a direct link like http://www.iageshacke.whateverimage.jpg
When you get that link post it in your topic and add the image tages around it [img]imageshackcodehere[/img]
make sure there are no gaps and your image should show
Image tags can be added by pressing the Img
tab while making or editing your post.