Ok here's what you do.
When you are going to post, click on the 'Go Advanced' button
Then at the bottom there's a 'Manage Attachments' click that.
Then browse your computer, till you find a picture you want to upload from your harddrive and upload it.
At that point your file will be uploaded to the post, then just go ahead and make a post.
You need to add 3 characters or something to make it post.
Also too, I think that there might be a size limit to it, but I'm not sure.