With iPhone 4.0 SDK, all graphics/images are automatically scaled (including coordinates) according to the device screen resolution. All we have to do is provide two versions of each image used in our application – one to suit for the retina display, other one suit to normal resolution. All images that needs to be rendered for retina display must have a “@2x” in the filename (just before the file extension). If the device uses retina display, it will automatically load the @2x file, otherwise it will load the normal file and scale it up.

About Me: Anish Kumar:
Mac OS X software development is my bread winner with over 6 years of experience. Expertise in Color Management, TWAIN Scanner drivers on Mac OS X, Photoshop Filter and Import Plugin development on Mac OS X, iPhone. As an hobby I love to work on PHP, Flex, AIR, Photoshop. Check the 'About' page for more.