I have a WKInterfaceImage in a WKInterfaceController and I'm generating the UIImage dynamically to display in the WKInterfaceImage. How do I find the maximum pixel dimensions that I can display in the WKInterfaceController for the image?
Use WKInterfaceDevice's screenBounds and screenScale properties to get the available screen size and scale.
Combine this with your knowledge of your app's user interface to determine the correct image size. Remember that WatchKit apps scroll vertically but not horizontally.