I'm guessing that many of you have run into the dreaded "not enough free space" message once while installing apps onto your iPhone even though the app should be small enough to fit. So why does the message appear? The truth is that, even though an app may report that it's small enough to squeeze into the last few gigabytes on your iPhone, every app is compressed before it's downloaded. This means that an app is transferred to your phone, uncompressed, and then the compressed version is discarded, effectively requiring a little more than twice the space of the reported size of the app.
So how much space does a large app need in order to be installed?
