I use the following code to customize the back button on the navigation bar throughout my application:
UIImage *backButton = [[UIImage imageNamed:@\"backButt
Try using this:
[[UINavigationBar appearanceWhenContainedIn:[YourClassThatsNotAUIImagePicker class], nil] setBackButtonBackgroundImage:someOtherImage forBarMetrics:UIBarMetricsDefault];
That should limit your appearance setting to only the classes you list and therefore leave the UIImagePickerController alone.