title: Unity building too large cubemaps
body: <p>I am using Unity 5.3.5 and am trying to implement 6 skyboxes in my project. Each skybox is at most 3mb in size but when i build my project, the app size becomes 87mb! I tried looking into details and found that each skybox converted to cubemap has been sized to 16mb(14.2%). This I saw found out from editor.log in</p>
  
  <blockquote>
    <p>%localappdata%\Unity\Editor</p>
  </blockquote>
  
  <p>I tried searching for this issue but found that this has been a known bug in Unity 4+. I need to decrease my app size! What should I do?</p>