Top sites icons not showing
(Crazy how I had to Google "How to post on Firefox forum" to post this. Anyway.)
My Top sites are not showing icons in some random cases (screenshot 1), and I can't understand what cases.
By default, the icons will show the first letter of the website name, i.e. "G" for Google Sheets, Google Forums, Google Drive etc. This is nearly useless, so I'm trying to add icons by linking the tiles to image files online (screenshot 2 shows WIX). However, some of them will show, some others won't.
I assume it has to do with the source of the image, whether it's official or not, but this still makes little sense. And if I add the website URL there instead of an image, it'll show me the full page in the icon, which wouldn't make sense to me.
How could I solve this?