Create Mac App for Graphic Design Utility

I need someone to create a Mac OS app utility for us. We are a design firm that produces many iPhone and Android apps and we'd like a tool that we can drag images on to which then displays the image as it would be displayed on a variety of Android and IOs devices. It will require two options - Crop and Scale - to allow the viewer to decide whether to display the image as if it was cropped equally on both sides or scaled to fit the different resolutions. Please see the attached excel document for the resolutions we'd like to support. For the largest of them (retina and 2560x1600 it should display at 50%). We will provide any buttons and interface elements as required to complete this. I will need the developer to seek out the resolutions of a variety of android devices so that we can select either a resolution or a device name (example Samsung Note or Nook Color) to display the image at. The app should be easy to use and straight forward. All source code created for the project will need to be provided at the end and will become our property. This will be our first Mac OS app, however we have many games in the queue to be converted from iPad as well as Flash so I look forward to a long relationship. Please provide examples of your work. Thank you.