pqiv is a powerful GTK 3 based command-line image viewer with a
minimal UI. It is highly customizable, can be fully controlled from
scripts, and has support for various file formats including PDF,
Postscript, video files and archives. It is optimized to be quick and
responsive.

It comes with support for animations, slideshows, transparency,
VIM-like key bindings, automated loading of new images as they appear,
external image filters, marks, image preloading, and much more.