i3lock:tldr:1c298

The command "i3lock --image ${filename-png}" is used to lock the screen of an i3 window manager session using a specified image as the background.

Here's a breakdown of the command:

• "i3lock" is the command itself, which is used to lock the screen.
• "--image" is an option or flag that specifies that we want to use an image as the lock screen background.
• "${filename-png}" is a placeholder for the actual filename of the image you want to use. This should be a PNG image file. You need to replace "${filename-png}" with the actual filename of the image you want to use.

Basically, when you run this command and replace "${filename-png}" with the actual filename of the image you want to use, i3lock will set that image as the background of the lock screen.