setBackgroundImage forBarMetrics image size?

Question

I am fairly new in iOS programming and I am creating my first app. I have been trying to use the following code to change the navigation bar background image (this is using the

Answer 1

Your image gradientBackgroundPlain.png should be 320x44, and create a second image named gradientBackgroundPlain@2x.png with a size of 640x88. Include the @2x image in your bundle, but continue to specify gradientBackgroundPlain.png for the name of the image. The platform automatically chooses the correct size image for use depending on whether there is a retina display present or not.