provides UI for sale images

First of (probably) many submissions from me for spree 1.3.

You might be aware of this already, but I think your branch might be misnamed (1-1-0-testing).

I was scratching my head while looking at the master branch (there's no UI code), and I figured out that this 1-1-0-testing branch was the current active branch, so i branched off of it.

I'm working exclusively on 1.3 right now, so that's what my pull requests will cover.