Feh

feh is a simple tool for viewing images.
You can view a directory as thumbnails, individual images, or set wallpapers.

Documentation

manpage

https://manpages.debian.org/buster/feh/feh.1.en.html

Usage

feh -.                        # show current dir as thumbnails
feh img.png                   # show image
feh --bg-scale img.png        # set image as wallpaper
feh --bg-scale --randomize .  # choose random image as wallpaper
feh --randomize -D 0.5 .      # slideshow images in cwd, change image every 0.5s (not for wallpaper mode)
~/.fehbg                      # restore last feh bg