How to get photo in Craig's List posting

I have 3 photos in an event album in my Air that I'd like to import into a Craig's List posting. How do I make this happen?

A Google search would have yielded this: LINK

When you click on the button in CL for uploading images, you'll get a file browser that looks like a Finder window. Near the bottom of the sidebar, you'll see a category called Media. Under that will be Photos where you can choose any images from your iPhoto or Photo Booth library.

Thank you so much Oneironaut. It was laughably simple to do with your clear instructions. I'm a total beginner and appreciate your reply.

My pleasure!