 <p>The easiest way to do it, is to record an App Preview for the biggest screen size and then scale it down with tools like After Effects or Final Cut Pro. I'm not 100% sure, if you can also do it with iMovie. If you're supporting iPad, you need to create another version for iPads.</p> <p>Here are the <a href="https://developer.apple.com/library/ios/documentation/LanguagesUtilities/Conceptual/iTunesConnect_Guide/Chapters/FirstSteps.html#//apple_ref/doc/uid/TP40011225-CH19-SW34" rel="nofollow">official sizes</a> (Landscape only for simplification):</p> <blockquote> <p>5 Series: 1920 x 1080 (&lt; Standard 1080p 16:9 aspect ratio) or 1136 x 640</p> <p>iPhone 6: 1334 x 750 (~ 70% of 1080p)</p> <p>iPhone 6 Plus: 1920 x 1080</p> <p>AppleTV: 1920 x 1080</p> <p>iPad: 1200 x 900 or 1600 x 1200 (4:3 aspect ratio)</p> </blockquote> <p>I suggest you capture the material for the App Previews with an iPhone 6 Plus (real device or simulator if that works for you) and then scale it down for the best quality. If you don't have an iPhone 6 Plus, you can use an iPhone 6, but you will lose quality.</p> <p><strong>Summary:</strong> You only need 2 different App Previews - with regards to resolutions - if you are only supporting iPhones. (3 if you are supporting iPads.)</p>