How to keep lock screen always on when connected to external monitor and charging I'm using a 3rd party utility to set very eye pleasing wallpapers on my 2013 MacBook Pro running macOS Mojave 10.14.2. Now I don't get to enjoy the beautiful sceneries in the background while I'm working but when I leave my desk, it would be really nice to leave the machine on (and locked) so that I can enjoy these gorgeous wallpapers. 

Attached is an example of my locked screen with an amazing background. I would like to keep it like this as long as the computer is charging and the lid is not closed. 

Note: I definitely do not want to the keep laptop running all the time especially with lid closed as I travel a lot for work. 

How might I achieve this?
You can use a utility called KeepingYouAwake. The app sits in the Menu bar and prevents your computer from sleeping (but lets the computer sleep normally when the lid is closed).

With the app running, your lock screen will not turn off. The app is simple to use with necessary configuration options available.