Step 1: You will need to have the pics hosted somewhere. ie. imageshack, or a few other free services. I use Earthlink for my service. You'll need to upload the pics to these sites based on their guidelines.
Step 2: You will need to view the picture on the site where it's hosted.
You do this then right click and HIGHLIGHT and COPY the picture location.
Step 3: Come here and post
type or click the IMG button above
It is very easy to do. feel free to email or iM and I'll fill in the blanks where I might have missed.
I thought I would try to help out a little too, its easy once you have done it a few times.
Photobucket.com is another good free picture host.
Once you have your picture hosted somewhere and you have copyed the address, You need to click the image button before and after pasting the address here. So click IMG button, paste address of your picture and click IMG again to finish the code.