You can store your downloads in your account when you signup!
Here is a close-up view of a black iPhone 5. Your product screenshot will look the premier in this portrait 640 x 1136 px mockup. The iPhone is being held up in the left hand. The distant background suggests a white wall with layered bricks to the left. On the brick wall is a framed painting.
Drag & drop not supported, but you can still upload via this input field: