Keep the wallpaper when movie restores the screen layout

.fehbg now saves its random picks to ~/.cache/wallpapers and redraws them with
--keep; screen-layout passes this through with --keep-wallpaper, used by movie.

.fehbg

@@ -0,0 +1,13 @@
+#!/bin/bash
+# Sets a random wallpaper on each monitor; with --keep, redraws the last ones picked instead.
+
+cache=${XDG_CACHE_HOME:-$HOME/.cache}/wallpapers
+
+if [[ $1 != --keep || ! -s $cache ]]; then
+    # One image per connected output, so --keep still has enough after an output was off
+    count=$(xrandr --query | grep -c ' connected')
+    shuf -n "$count" -e ~/.local/share/backgrounds/random/* > "$cache"
+fi
+
+mapfile -t walls < "$cache"
+exec /usr/bin/feh --no-fehbg --bg-fill "${walls[@]}"