"Save As" and "Print" to mouse right click context menu
Could you add "Save As" to mouse right click context menu so you can save changes that you have made to the image. And "Print" so you can quickly print an image. Mouse right click menu is very useful in full screen mode. And maybe you could even consider adding all the tabs from menu toolbar ("File", "Tools", ...) to mouse right click context menu (except "?" tab that contains "check for updates", "about", ...), because different people need different shortcuts to functions. The best solution would be that you let people choose functions for their own mouse right click context menu in program settings (with check boxes), but that would require more coding work.