Completely dumb question: How do you post pics? :s
It's very simple. Find somewhere to host the picture (like Photobucket, something similar or your own website). Then, when you start a new post, clickity-click the "insert image" button and put in the image's file address into the pop-up window. If you did it correctly, the image should show in your post when you hit the "OK" button. If not, you did something wrong.
And two things to remember, images shouldn't be any more then 600 pixels wide and hot-linking is a no-no.