title: Phaser: background image issue
body: <p>So, i have this problem, i'm doing that "flapy bird" game with Phaser, but when i put a background image moving, the other images (like the bird, pipes, and everything) won't display, and i don't know why, any ideas?, here's my code:</p>
  
  <pre><code>// Initialize Phaser, and creates a 400x490px game
  var game = new Phaser.Game(400, 490, Phaser.AUTO, 'game_div');
  
  // Creates a new 'main' state that wil contain the game
  var main_state = {
  
      preload: function() { 
          // Change the background color of the game
          // this.game.stage.backgroundColor = '#71c5cf';
  
  
          // Load the bird sprite
          this.game.load.image('bird', 'assets/bird2.png');
          this.game.load.image('pipe', 'assets/pipe.png');
          this.game.load.audio('jump', 'assets/jump.wav');
          this.game.load.image("background", "assets/background.png");
      },
  
      create: function() { 
          // Display the bird on the screen
          this.bird = this.game.add.sprite(100, 245, 'bird');
          this.pipes = game.add.group();  
          this.pipes.createMultiple(20, 'pipe');
          this.timer = this.game.time.events.loop(1500, this.add_row_of_pipes, this);
          this.score = 0;  
          var style = { font: "30px Arial", fill: "#ffffff" };  
          this.label_score = this.game.add.text(20, 20, "0", style);
          this.jump_sound = this.game.add.audio('jump');
          this.bg= game.add.tileSprite(0, 0, game.stage.bounds.width, game.cache.getImage('background').height, 'background');
  
      // Add gravity to the bird to make it fall
      this.bird.body.gravity.y = 1000;  
  
      // Call the 'jump' function when the spacekey is hit
      var space_key = this.game.input.keyboard.addKey(Phaser.Keyboard.SPACEBAR);
      space_key.onDown.add(this.jump, this);
      this.bird.anchor.setTo(-0.2, 0.5); 
  },
  
  update: function() {
  
          // If the bird is out of the world (too high or too low), call the 'restart_game' function
          if (this.bird.inWorld == false)
              this.restart_game();
          this.game.physics.overlap(this.bird, this.pipes, this.restart_game, null, this);
  
          if (this.bird.angle &lt; 20)  
              this.bird.angle += 1;
  
          this.game.physics.overlap(this.bird, this.pipes, this.hit_pipe, null, this);
          this.bg.tilePosition.x -= 1;
      },
  
  // Make the bird jump 
  jump: function() {
      this.jump_sound.play();
      if (this.bird.alive == false)  
      return; 
      // Add a vertical velocity to the bird
      this.bird.body.velocity.y = -350;
  
      // create an animation on the bird
      var animation = this.game.add.tween(this.bird);
  
      // Set the animation to change the angle of the sprite to -20° in 100 milliseconds
      animation.to({angle: -20}, 100);
  
      // And start the animation
      animation.start();
  },
  
  // Restart the game
  restart_game: function() {  
      // Start the 'main' state, which restarts the game
      this.game.state.start('main');
      this.game.time.events.remove(this.timer);
  },
  
  add_one_pipe: function(x, y) {  
      // Get the first dead pipe of our group
      var pipe = this.pipes.getFirstDead();
  
      // Set the new position of the pipe
      pipe.reset(x, y);
  
      // Add velocity to the pipe to make it move left
      pipe.body.velocity.x = -200; 
  
      // Kill the pipe when it's no longer visible 
      pipe.outOfBoundsKill = true;
  },
  
  add_row_of_pipes: function() {  
      var hole = Math.floor(Math.random()*5)+1;
  
      for (var i = 0; i &lt; 8; i++)
          if (i != hole &amp;&amp; i != hole +1) 
              this.add_one_pipe(400, i*60+10);
  
          this.score += 1;  
          this.label_score.content = this.score;
      },
  
      hit_pipe: function() {  
      // Set the alive property of the bird to false
      this.bird.alive = false;
  
      // Prevent new pipes from appearing
      this.game.time.events.remove(this.timer);
  
      // Go through all the pipes, and stop their movement
      this.pipes.forEachAlive(function(p){
          p.body.velocity.x = 0;
      }, this);
  },
  };
  
  // Add and start the 'main' state to start the game
  game.state.add('main', main_state);  
  game.state.start('main'); 
  </code></pre>