First off, I think you need 10 posts, so surf around and stay off the off topic and for-sale threads since they don't generate post counts. Then you can upload pictures by clicking below the message box GO ADVANCED and then MANAGE ATTACHMENTS toward the bottom of the screen, in ADDITIONAL OPTIONS section. Make a couple more posts to this thread and your count should go up.
Another thing you can do is upload your pictures to a saved location on the internet, photobucket, etc. Then go to that picture in another window, right click on the picture and choose COPY IMAGE LOCATION, and then come back here and click the little yellow box at the top of the message box, looks like a picture of a mountain with a square sun above it, to the right of the Bold, Italics, Underline options. Click that box and right click in the space and PASTE and OK and the picture will appear directl in the message.