function preload ()
{
this.load.image('atari', 'assets/sprites/atari130xe.png');
}
function create ()
{
// setScale sets the x and y scale values
this.add.image(100, 300, 'atari').setScale(0.5, 0.2);
// If you just provide one value then both x and y are set to it
this.add.image(400, 300, 'atari').setScale(2);
var image2 = this.add.image(800, 300, 'atari');
// You can also set the scale via the scaleX and scaleY properties:
image2.scaleX = 0.5;
image2.scaleY = 4.5;
}