File manager in Ubuntu 20.04 not showing thumbnails

The file manager that came with my installation ("Simple file manager for Gnome") doesn't show thumbnails for jpg, png, and videos. I've gone to /Preferences/Search & Preview and made sure it's set to always show thumbnails but it doesn't. How can I fix this?

Install FFMPEG Thumbnailer

sudo apt install ffmpegthumbnailer

Then close and reopen file manager. Thumbnails for most video files should generate now.

Otherwise, delete ~/.cache/thumbnails and restart your computer