I'm building an application for cataloguing an analogue photography collection (slides and negatives). I'm using a scanner has frames that hold the negative strips or slides in a fixed position on the scanner bed, so I can grab previews based on fixed positions. However the photos may have been captured landscape, so I want a function to select the orientation of the images. The common implementation of this is a pair of buttons to rotate the image either clockwise or anticlockwise. I find this slow to use as I can (usually) quickly look at an image and identify it's current orientation, but I can't quickly translate that identification into a required rotation. I'm currently using a collection of four buttons, one for each cardinal direction, such that clicking one identifies that direction as the top of the image. This is working well for me as I can quickly look over a batch of images and click the button for each one.
While this works for me (and at the moment it only has to), I think that if I were to make the application available to other people, this would be a problem area as the feedback to the user that they have selected the correct orientation is poor, being only a selected radio-type button, with no change in the visible preview. What is the best way to signal to a user how the feature works?