Android Nikon DSLR Downloader

We are looking to create a simple Android Nikon DLSR interface app that recognizes when an image has been captured by a Nikon camera connected via USB OTG. When an image has been captured, the app will download the image and present a thumbnail view to the user. When the user presses "save," all images in the thumbnail view will be saved to the device. Please refer to attached PDF for more information and specifics on how the app should behave and sample screen layouts. Existing open source projects may be used to support the PTP functionality provided they are properly attributed. We will handle all aspects related to code signing and distribution.