You didn't include the "Help > Troubleshooting Information" info with the installed extensions, so we won't be able to give precise instructions. Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance). *Do NOT click the Reset button on the Safe Mode start window. If it works in Safe Mode and in normal mode with all extensions (Firefox/Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears. Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit) *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Try disabling the add-on you used and let's see what happens ok. https://support.mozilla.org/en-US/kb/disable-or-remove-add-ons?esab=a&s=remove+background+images+from+adon&r=3&as=s