You don't even need to download a package, there are websites that do it for you. Source: about 1 year ago

What do you mean by that? For iphone, you have to select the right ones im xcode. For android, make sure to check out the docs: https://www.construct.net/en/make-games/manuals/construct-3/tips-and-guides/icons-splash to see which types of icons you have to create. You can also automatically generate some of the required icons, not the dynamic ones however (makes sense as you need 2 layers for them) using this... Source: about 1 year ago

I use https://appiconmaker.co. The only issue is that you need to manually open every icon in preview, go to file > export as (I think) > and then uncheck the "alpha" (this will cause you problems when uploading to the app store.). Source: about 2 years ago

When you have an app that is ready to go the stores, you must have an app icon. And you have one because your design team did a great job on creating one! But you must have them in a couple of specific dimensions, with square and rounded corners, for both iOS and Android. To spare yourself and designers from this time consuming and boring task, there are some web applications that can do that for you, and the best... - Source: dev.to / over 2 years ago

I’ve used https://appiconmaker.co/ in the past. Source: almost 3 years ago

There is also web-products like this doing different versions: https://echowave.io/. Source: 7 months ago