Tween Problem duplicate image

[i3Designer]

create: function(){  

        this.creaNemici();

    },

 

 

creaNemici: function(){

        

        this.nemico = game.add.sprite(-100,20,'nemico');

        this.nemico.anchor.setTo(0.5,0.5);

        game.physics.enable(this.nemico, Phaser.Physics.ARCADE);

   },

 

update: function(){

        

        game.add.tween(this.nemico).to( { x:game.world.centerX,y:game.world.centerY }, 1300,Phaser.Easing.Linear.None, true);

 

},

 

I have a problem with the tween. I create an image and want it follows the position of an image. To test I set that the enemy has to go in the center of the world, I have done as above by removing the piece of code that was not interested. But I start, the game show two images.

 

PS: In localhost I see two pictures, but if I do the screenshot, you can not see. is the render?

[eguneys]

don't add tween in the update method, update method gets called on every frame, like 60 times per second. add your tween in create method.

[i3Designer]

don't add tween in the update method, update method gets called on every frame, like 60 times per second. add your tween in create method.

But I want to do that the enemy is always running towards the object

[i3Designer]

I tried a lot, and I settled with: 
game.physics.arcade.moveToObject