They are free and just require you to register. Then you can upload your pictures there. They will give you links already made for message board. It will be the one with the "
" tags in front of the URL.
If you want to post a picture that is already on the web just get the address by right clicking on the picture and going to the properties. It will give you the URL for it. Then past it on your reply box and put the image tags in front of you like so: