Changing splash / lock screen

I'm not a big fan of the very white Linux Mint login / lock screen. So I decided to change it to match my desktop background, which is a typical dark thinkpad theme that I've been using on all my machines for years. Here's how to make the change: cd /usr/share/backgrounds/linuxmint sudo ln -sf .jpg default_background.jpg sudo ln -sf .jpg Talento-1.jpg sudo rm /var/lib/gdm3/.cache/wallpaper/* Not sure if you can use BMPs or other images. Since my background image is a BMP, I decided to play it safe and convert it to a JPG rather then find out the hard way.