iPhone 5 - what naming convention the new images have to follow?
The new default is Default-568h@2x.png. (note hyphen)
There is no other corresponding change. If you need a different image for the new iPhone 5 screen then you have to create it as a separate name. There is no 1x/2x/new phone auto switching behavior.
If you are looking for something similar to ~iPad or ~iPhone (like ~586h) there isn't anything build in like that. But you can easily add it yourself by expanding UIImage class.
Have a look at this source snippet (UIImage+Retina4) for information about how to achieve. Just add this UIImage category and there will be support for ~568h@2x files.
I solve this problem here. Just add @2x~568h suffix to images or ~568h to xib's. Also you can use this images in xib's.