GPicView

The default image viewer on Ubuntu is Eye of GNOME (EOG). It appears with the generic name Image Viewer in the menu. It can handle most image formats and is a good default image viewer. However, it takes several seconds to load up the first time it is used or if it is used after a long time. I find this highly irritating and started searching for a replacement.

GPicView is a simple image viewer that is built purely for speed. Whether launched the first time or anytime, it loads up in a flash with the image. No matter what the size of the image, this viewer is just super fast. Among the many image viewers I tried for their loading speed, this turned out to be the fastest. This is now my default image viewer 😊

To install GPicView:

$ sudo apt install gpicview

Confusingly, GPicView too appears in the menus with the generic name Image Viewer. It has a different icon, so that may help you distinguish it.

Tried with: GPicView 0.2.4 and Ubuntu 14.04