Awesome

A pan-and-zoom image slideshow for Linux

Written in Python using Clutter (via PyGObject).

It can work as a standalone command-line utility, or as a "component" of Variety Wallpaper Changer (https://peterlevi.com/variety).
Run it with "--help" to see options.

If you also have Variety installed, it will provide a tab in its preferences for configuring and running Variety Slideshow, i.e. Variety serves as the GUI frontend for the Slideshow. variety-slideshow is listed in the Recommends section of Variety's package.

Demo and more info: http://peterlevi.com/variety/2016/02/0-6-0-released-with-variety-slideshow/

Installation on Ubuntu

sudo add-apt-repository ppa:peterlevi/ppa
sudo apt-get update
sudo apt-get install variety-slideshow variety