如何获取存储在设备中的所有图像，并在iPhone sdk中将它们显示为图库

I want to get all the images stored in the device and show them as gallery in my iPhone app. UIImagePickerController shows all the photos in thumbnail view and on selecting each photo we get the data of that particular selected image only, instead i want to get all the photos at one shot and show them as gallery. Is this possible, if yes please tell me how to do this. What is the use of AssetLibrary ?. Does it help what I need to achieve.If yes, please tell me how to achieve this using AssetLibrary. I want to get all the images stored in the devi