CIContext createCGImage returns nil in iOS Simulator

Question

I am using the code provided in this SO answer.

It works for most images, but when I had an image that I cropped using the built-in Photos app, I kept getting nil from the [context createCGImage:fromRect] call. After spending a lot of time trying various things and coming up empty, I decided to try it on my iPhone 5, and to my surprise, it worked!

Is this really expected to fail in iOS Simulator? Or is there something else I need to do to make it work in the simulator?