I am completing some design work on my application. Following a few people saying it is best to design for the iphone5 (4inch) screen first I have completed a page design for the retina. The image has then been sliced (cut up) as required for the iphone.
In terms of scaling down for the iphone3/4, is it best just to load the image in photoshop and use Edit > Image Size... to bring the size down, or create a new image the correct size and scale all the layers down using Ctrl + T and shift to transform?