Improve "Show preview" option to use fewer ram (as an option)

I like the option to show the preview of the window, but I feel that it is using way too much ram for just a few windows open.

For instance before hovering over the group buttons the ram usage of the plugin is about 45MB. With just 6 window / group buttons opened the memory quickly raises to 117 MB...

I wonder if a quality setting for the preview could be added so we could choose smaller resolutions (or worse quality for the preview) as a trade for way less ram consumption. I believe KDE had a setting for this.