Via `UIImagePickerController`, is there a way to tell if the image the user chose from their library is a screenshot? Also, is there a timestamp associated with screenshots? I've read [Get Exif data from UIImage - UIImagePickerController](https://stackoverflow.com/questions/9766394/get-exif-data-from-uiimage-uiimagepickercontroller), but do screenshots in particular have this data?