sxiv is an alternative to feh and qiv. Its only dependencies besides xlib are
imlib2 and giflib. The primary goal for writing sxiv is to create an image
viewer, which only has the most basic features required for fast image viewing
(the ones I want). It has vi key bindings and works nicely with tiling window
managers. Its code base should be kept small and clean to make it easy for you
to dig into it and customize it for your needs.

Features
* Basic image operations, e.g. zooming, panning, rotating
* Customizable key and mouse button mappings (in config.h)
* Thumbnail mode: grid of selectable previews of all images
* Ability to cache thumbnails for fast re-loading
* Basic support for multi-frame images
* Load all frames from GIF files and play GIF animations
* Display image information in window title

Homepage:
https://github.com/muennich/sxiv
