The Image Viewer addon gives the possibility of integration with external modules via commands.
Now it is possible to combine Image Viewer and Single State Button addons via next() and previous() commands. Selecting the Next or Previous button changes the currently displayed frame in the Image Viewer addon to the next or previous one (or first/last if the last or first frame was displayed).
Updated documentation on an Image Viewer addon is available here. If you wish to view a short demo presentation, click here.