How Does iOS Resize/Scale Button Images?

Question

Does anyone know how Apple does this? Here's the problem I have. I have some images that are very high-res. When I create a button and set the background image to one of these images the resolution is crystal clear.

Then if I take that same image and using (and believe I've tried a lot of suggestions) and I reduce the dimensions the image always come out blurry. And the images are all 354 x 354 that I"m downsizing to 40x40.

So if you know what method Apple uses to get crystal clear smaller versions or thumbnails please let me know.

Thanks!

Answer 1

All the iOS devices right now have retina screens. That means that your 40 x 40 image is actually an 80 x 80 image (or even different with the new iPhone 6(+)). When you size the button, the dimensions are in points but when you resize using Photoshop, you're going all the way down to 40 x 40.