22MB of resources = 70MB in build?

Unity Engine
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1

I develom a game, it’s resources is only 22MB ,but after build, it become 70MB…

  1. some Texture is change to PVRTC, but some of them I use true color to show, because only true color can performance of high-quality images.and how I can do?
    Especially the background, PVRTC become blurred

  2. In addition to pictures, are there other things that affect the size of it?

thanks

2

There is dedicated Unity manual section : Unity - Manual: Optimizing the size of the built iOS Player