Yes Dave ( @just) is right. The best place for your art pieces to be is in your personal Album. If you do that they will get displayed on the first page of the forum along with everyone elses. Also you can categorize them by making several albums and when someone visits your page they can browse through all your work.
However in order to discuss your pieces it's also good to put them in a thread such as this. This is how you will get suggestions from other members.