如何使用图像视图从图像阵列创建随机图像生成器？

I want to generate a random background image from a UIImage array so every time the view loads a new background image is randomly selected from the elements of the array. I currently have the background image connect to an IBoutlet UIImageView. I've tried using arc4random but it gives me an error when I try to randomize the elements of the UIImage array by saying I cannot attach a int subscript to a UIImage. Any suggestions how to about this?I want to generate a random background image fr