Single Image Gallery Random Thumbnail

I created a single image gallery and set the order to random. I anticipated the thumbnail for the gallery would change to a random image each time the page was viewed but it is always the same. Maybe I am misunderstanding how this is supposed to work but it would be really nice if the thumbnail would change according to the gallery settings.

Is there another way I can achieve a single random image from a gallery if this isn’t the way the single gallery image is supposed to work?

Many Thanks

https://ww.wp.xz.cn/plugins/foogallery/