You can scroll specifically through Key Images using the Scroll to Next Key Image function.
To use the function, press and hold the Ctrl key on the keyboard as you use the mouse to scroll (use the middle scrolling wheel on the mouse).
The Scroll to Next Key Image function advances you to the next original image marked as a Key Image.
NOTE: If there are several instances where the same image is marked as a Key Image, you will advance to the next image, because the original image only shows one instance.
You can toggle dynamically between two scrolling modes.
While you press and hold the Ctrl key and use the mouse to scroll simultaneously, you will scroll through Key Images only.
While you use the mouse only to scroll, you will scroll up or down to further explore proximate slices.
Press K on the keyboard to automatically scroll through the series to the next Key Image.