Learn how to use Axure to produce rapid prototypes that seem more like a finished product. You can allow users to input data, carry user data from one screen to another, or do different things depending on conditions you set.
A sandwich isn't two dimensional and the final hand off of images to your designer shouldn't be either. An original image file contains all the layers, just like a sandwich. Travis created this handy list of tips that you can use to work with your designer to make sure you know what to request from your marketing or creative team.