Many stock images such as on lets’s say for example Anonymity Operating System Comparison - Whonix ™ vs Tails vs Tor Browser Bundle (which is this image File:Balance-154516-640.png - Whonix at time of writing) are indeed not very customized. These are more of a stopgap than perfect. But that stopgap could go on for years.
Would it be better to have no such thumbnail than a just only good enough one? I think it’s useful to have one that is at least good enough than not having one at all. That is because when these links are shared then on social media, discourse forums, telegram the thumbnail will be shown which leads to better viability, more attention, I think.
Also called illustrative images. Related: Missing Libre Illustrative Images
The illustrative image on…
… looks not stock, looks better, more suitable? Yeah. Something like that for other pages would be nice. Help welcome and without help might not materialize over the years as I am not much working on graphics.