You can store your downloads in your account when you signup!
An iPad is being held up by a woman, laying back on her bed with her feet up, holding on to this iPad, taking a look at your app. The iPad holding an image of 1024 by 768 pixels for your mock up. The woman is wearing a gold watch, black pants and white tank top. She’s resting at home and enjoying your website or app. This stage will be perfect to show a video-watching or a movie-sharing type app.
Drag & drop not supported, but you can still upload via this input field: