Background image can not be automatically filled in after turning the problem

I added in a xib file a UIImage View as background image, the original image resolution is small, I chose Scale to fill, in the case of the vertical (Portrait / PortraitUpsideDown) picture can be enlarged to full screen, but rotated to the horizontal ( ) When Landscape background image back to its original size, leaving the white part. In addition, if the state first in the Landscape, images are also automatically fills up, but after turning it appeared the same phenomenon. How can this be resolved?
Reply:
In turning over there to reconfigure fill
Reply:

cited a floor cloudhsu reply:

there to re-set the rotation to fill

Agree upstairs view
Reply:
2nd floor with view to re-set the fill