title: SKTexture preloading
body: <p>When you preload textures using the spritekit preloadTextures function, it loads all the textures in the provided array into the memory at once.</p>
  
  <p>If you don't have the ability to split up your levels in your game with 'loading screens' but do have separate levels with different image files than each other, how can you keep from storing all the images in memory at once without sacrificing frame rate when spritekit loads the images when it needs to?</p>