So to upload images, just click the photo button to the right of the post as (username/real name) button. As you can see, it is available for the main post box, as well for reply comments (which is sorta expected, but I showed a reply box anyways). You can also drag and drop images from your computer, which is new for Disqus 2012 because this was not available in the classic Disqus. You can see a picture of it below.
[Space Between Images]