In the tool header pane, roll your cursor over the icon that looks like 2 mountain peaks. It should say "insert image". Click it, and paste the url of your picture. Do it as many times as you have pictures.
2 things right off the bat... New to the H.A.M.B.? Introduce yourself here! and Read This First! Then ask away...or look in Questions & Suggestions There are numerous threads on posting pics a bunch of different ways. Antny's answer only works if you have the pic up on Photobucket or another host.