Set a light and dark wallpaper

The wallpaper lives under [wallpaper]. image is the picture for light mode and image-dark the one shown while glimpse is dark; without image-dark, image shows all the time. Which one shows follows [appearance] color-scheme: desktop follows the desktop mode set by desktop-color-scheme, while light or dark keeps one picture up. With color-scheme = "light", you keep the light picture even when the desktop is dark. The full setting list is in the wallpaper reference.

[wallpaper]
image = "~/Pictures/dunes-day.jpg"
image-dark = "~/Pictures/dunes-night.jpg"

Without any image, glimpse shows its built-in picture. A path can start with ~/; a relative path is looked up in ~/.config/glimpse/.

fit decides how a picture that does not match the screen is drawn: cover (the default), contain, fill or center. color paints underneath whatever the picture leaves open, and is also what you see when the image file is missing.

A different picture per monitor

[[wallpaper.outputs]] overrides the main table for one monitor, named by its connector. A field you leave out falls back to [wallpaper], one by one, so set image and image-dark together: an entry with only image still takes the dark picture from [wallpaper].

[[wallpaper.outputs]]
monitor = "DP-1"
image = "~/Pictures/garden-day.jpg"
image-dark = "~/Pictures/garden-night.jpg"

An entry for a monitor that is not connected is ignored. glimpsectl applet list shows the connector names of monitors with a bar, and your compositor lists them all (for example niri msg outputs).

If the picture does not change

glimpse keeps the previous picture when a file is not an image it can read, and paints color when the file does not exist. Both cases are only logged, and glimpsectl config validate does not catch them, so check the path first.