When an app downloads, the size described on the App Store is smaller than what storage says. Sometimes a 100 megabyte difference, with other apps it can add up to 1 gigabyte. What can I do about it? I delete and re-download although nothing changes. Check the app size of an app on the App Store and the true size of the app in storage. I don't mean the data Included, touch the app in storage to read the basic app size. Can someone explain this to me? Is it that the app decompresses after installation.