The online documentation (
http://imagevuexcom/153 ) only list the "thumbopenwin" options as popup, true, and false, but I found entering "slideshow" opens the image within a slideshow.
You could also disabled thumbrightclick for the sake of simplifying the user experience.
You then should edit slideshowimagevue.ini to change the view and behavior of the opened images/slideshow. Check the "main controls", right click, and key controls to be sure downloads turned off (
https://www.photo.gallery/448 ).
If I understand your issue correctly that might do it for you -;)