Yes, use a different image for each version. You check check for iOS 6 with
NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1
Apple alludes to this solution in their iOS7 transition guide
Question
What is the best practice for selecting the correct navigation bar background image depending on the iOS version?
As I understand it, the image should be a height of 64px for iOS7 and 44px for iOS6. Is it simply a matter of checking the iOS version running and then choosing the appropriate image (in an if statement)? Is there a way to do it in interface builder? Or better yet, is there a way to have iOS select the correct image automatically (based on the file name, etc.)?
La solution
Yes, use a different image for each version. You check check for iOS 6 with
NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1
Apple alludes to this solution in their iOS7 transition guide