They don't work because of how our data is structured in the backend.
You can choose to display thumbnail images if you'd like. In your Views (in the Factory) change occurrences of [product.image
That will display the smaller version if it exists.
I would also recommend following the 5 steps I outlined (in my point 1) here: /show...2469#post52469
That will help speed up image loading on your site.