Storing the image in the appdelegate would definately work, but it's not really the way to go.
Could you explain your situation a little more in detail? Do you have a reference to the Game object in your viewcontroller? Atleast in some viewcontroller you should. Then you can set your image like so:
Code:
myGameObject.imageView.image = image;
That is, if you have that instance variable synthesized correctly. And you could set your Game object as an instance variable in the viewcontroller.