Photographs always work well particularly with folded items such as packaging to show how they work, but you can sometimes lose out on the detail of the work.
Whereas displaying the design straight from the application presents the colours and detail well on screen it can lack the third dimension of a photograph!
One solution could be to Photoshop your designs onto a photograph of the product, combining the best of both:
http://abduzeedo.com/using-the-vanis...ilter-tutorial