title: Why is SKSpriteNode(fileNamed:) generating nil in iOS using Swift?
body: <p>Why is init(fileNamed:) of SKSpriteNode generating a nil?</p>
  
  <p>I've tried the following code. I show only the code that is related to the problem:</p>
  
  <pre><code>let road = SKSpriteNode(fileNamed: "road.png")
  
  override func didMove(to view: SKView) {
  
      print("road", road as Any) // road nil
      if let road = self.road {
          road.position = view.center
          road.physicsBody = SKPhysicsBody(rectangleOf: road.size)
          print(road.physicsBody?.isDynamic as Any, "!")
          road.physicsBody?.pinned = true
          addChild(road)
      }
  
  }
  </code></pre>
  
  <p>I get a nil regardless of whether the image file is a regular png or an animated png file.</p>