Switch tab screen not showing page image on iPad

With so many tabs open seeing this image helps remind me which tab is which. Now I have to open each tab to view it whereas previously you could easily scroll through all your tabs and see almost a thumbnail image of where you last left off on that particular page. 

Is there a way to restore seeing this image or change settings? Could it be something to do with background page refresh - is there a way to switch this off for iPad so a page only refreshes when I open that tab? I don’t appear to have this issue with my iPhone, just viewing open tabs on my iPad. I have significantly less tabs open on my iPhone compared to my iPad, could this also be causing the issue?

Hopefully this post makes sense and I’ve posted it in the right section! Any help given will be greatly appreciated.

Thanks in advance.