What are some alternatives?
AppIconizer - Icon generator for App Store & Play Store submissions.
EasyAppIcon - EasyAppIcon helps you to create your own app icons easily. Supporting Android Adaptive Icon!
MakeAppIcon - MakeAppIcon resizes and optimizes your icon designs into all formats needed for iOS and Android mobile app!
Logo Foundry - Logo Foundry is a professional Logo Design Suite App for Android and iOS that let's you create professional branding for your business in Minutes.
Appicon - Generate app icons and AppStore screenshots with just one click.
LogoScopic - Create a logo in minutes on your iPhone