You can store your downloads in your account when you signup!
You can set your app on this iPhone 5s gold, sitting on a white desk, to really show it off. This stage has a white and blue-gray type color scheme that would contrast well with any brightly-colored app mockup. The iPhone 5s will hold an image of 645 by 1136 pixels in portrait view. On the desk, you’ll also get a light-brown box and a marker. And off to the side, a chair, a nice plastic chair.
Drag & drop not supported, but you can still upload via this input field: