By refer to [/questions/1271362 Is there a way to change only the background image for new tabs?], I set the background image on firefox homepage, but how to save into firefox/questions/1271362 account as a profile which callable when access into firefox account everywhere? --- [quote] Thank you very much @cor-el for your solution. It worked. Here I will just modify what you said, so that others can benefit with the exact steps. If you are using Firefox 70+ versions on Linux, like me: 1. Go to about:support. And look for the "Profile Directory" button. 2. On the opened directory, create a folder called "chrome" if it doesn't exist. 3. Create a file called userContent.css, and paste in the following contents: ``` @-moz-document url-prefix(about:home), url-prefix(about:newtab) { .click-target-container *, .top-sites-list * { color: #fff !important ; text-shadow: 2px 2px 2px #000 !important ; } body { background: url(/usr/share/backgrounds/flowers-4564439.jpg) !important ; background-size: cover !important ; } } ``` Save the file and open Firefox (no need to restart at this point). - replace the url(...) with the image path. Here, in my case I have images in the /usr/share/backgrounds direcotry (remember using full path) - The `background-size: cover !important ;` line here means that the image will be resized automatically]. - Everything is self explainatory here - IDK how to format codes on support.mozilla.org 4. Open the url about:config, and change the option "toolkit.legacyUserProfileCustomizations.stylesheets" to true. 5. Restart firefox. It should look more awesome now! [//quote] Reference : firefox preference url : 1. about:profiles 2. about:support 3. about:config