Upload the pic to a photo sharing site like FLICKR or TINYPIC, then copy the html links and paste to your post....

I use tinypic, its really easy. Just add the code and you have pics! add the top code (HTML for websites)

{{gwi:2139766}}

{{gwi:2139767}}

Here is a link that might be useful: tinypic

Or photobucket works too.

Past the links into the post one by one.

I just use the browse box above the reply box and find the picture I want on my computer, highlight it and click on open. You don't have to have a hosting site if you have the photos on your PC.