Typically this value is 2.0 on Retina-display devices.
The resolution of the MonoTouch.UIKit.UIImage in pixels, is equal to this value times the UIImage.Size. Images for Retina-display devices will typically have a UIImage.CurrentScale of 2.0. Files whose names end with "@2x" will automatically load with a MonoTouch.UIKit.UIImage.CurrentScale of 2.0
This can be used from a background thread.