Just a quick little tip as a result of my work today: if you, like me, discover that the total size of all your loading screens on iOS is massive - there is hope!
My full set of (detailed and full-colour) loading screen PNG images was ~25MB. I managed to reduce this to 3.5MB by:
- Making the unused portrait images for iPad and iPhone 6 completely black (the game is landscape only - note that you still need the rotated images for the other iPhones as they're shared between portrait/landscape). Saved almost 11MB.
- Using a PNG reducing website to compress the rest a bit more harshly (I used https://tinypng.com). The quality afterward was acceptable and it saved another 11MB.
Pretty simple steps for a huge download size reduction bonus!