I am serving PNG images locally to customize the newtab page icons, this have been working for a long time now. I set the icon once and apparently firefox stores it in the thumbnails/ folder, inside the local profile folder.
You can find the paths being saved in the setting browser.newtabpage.pinned in JSON
The entries are like this:
{"url":"","label":"","customScreenshotURL":"<>.png"},
In the html of the actual new tab page, they look like this:
style='background-image: url("moz-page-thumb://thumbnails/?url=http%3A%2F%2F127.0.0.1%3A5002%2Fcontent%2FjqOpOOd.png&revision=4863");'
I tried deleting the files in thumbnails/ in the local firefox folder, this causes all the icons I set to disappear.
Selecting a new icon doesn’t work either.
Firefox doesn’t try to to request the icon, even though the icons are not showing properly.
Apparently, firefox seems to store a mapping of old image paths somwehere, even when the thumbnails/ folder is deleted, but they cannot be updated or shown.
Clearing history or the cache, or deleting the cache2/ folder doesn’t solve it. I explored different sqlite files with databrowser.
Any clue, suggestion or idea?
