title: How to load image with same method in both retina/non-retina screen under OS X that's not in the Resources directory?
body: <p>I knew that in [NSImage imageNamed] method, it will try to load retina image on Retina Mac while load non-retina image on Non-Retina Mac, but it was only applied on Resources directory,  is there any other method can do the similar thing on other user-defined directory ? </p>