Apple emailed "Your app, Dualgram, may be featured on the App Store". Any ideas for artwork?

Received a good news from Apple! I need to come up with the promotional artworks within 4 days, which I am 🤯 over. If anyone has good idea of a hero artwork (https://help.apple.com/asc/appsp...), please help 🙏🏻🙏🏻 More info: Dualgram was launched a week ago (http://producthunt.com/posts/dua...). It records both the front AND back cameras of iPhone. An obvious artwork is to use the show the iPhone recording (see cover image in http://dualgram.com), but that is against the guideline.