I'm working on a wizard of sorts that first takes in systems that a client is interested in.

As you can see, the selection is full of dead links, since we're not sure if we want to use icons or hi-res images just yet. I guess I'm still pretty stumped on the design direction of this, and how usable this interface is.
Looking for opinions mostly, and my main question is, what is the most optimal way of displaying a range of choices to a user pictorially while indicating that more than one choice can be made?