You can store your downloads in your account when you signup!
You can use this white iPhone 6 mockup on a metal stand to show off your app. It is set against a classic white background. The iPhone 6 mockup is set to portrait view and holds an image of 750x1334px. This will work well for any type of app. It would be especially fantastic for apps with a modern design.
Drag & drop not supported, but you can still upload via this input field: