Edit: Due to the fact that this article is old, the installation instructions may not work anymore. In order to successfully install the latest version of Nomacs, please access the nomacs tag and open the latest article (the one on top).

The latest installation instructions for Nomacs
Hello Linux Geeksters. Nomacs is an open-source image viewer, working on Linux and Mac OS X, under the GNU General Public Licence v3. Nomacs is lightweight and fast and has support for all the popular image formats, like JPEG, PNG, GIF, ICO, BMP and RAW. The latest version available is Nomacs 2.0.0, which has been recently released, coming with changes and improvements.
In this article I will show you how to install Nomacs 2.0.0 on Ubuntu 14.10 Utopic Unicorn, Ubuntu 14.04 Trusty Tahr, Ubuntu 12.04 Precise Pangolin, Linux Mint 17 Qiana, Linux Mint 13 Maya, Elementary OS 0.3 Freya, Elementary OS 0.2 Luna, Pinguy OS 14.04, Pinguy OS 12.04, LXLE 14.04, Linux Lite 2.0, Peppermint Five, Deepin 2014, and other Ubuntu derivative systems.
Because it is available via PPA, installing Nomacs 2.0.0 on the listed Ubuntu, Linux Mint, Pinguy OS, Elementary OS, Deepin, LXLE, Linux Lite and Peppermint systems is easy. All you have to do is add the ppa, update the local repository index and install the nomacs package. Like this:
$ sudo add-apt-repository ppa:nomacs/stable
$ sudo apt-get update
$ sudo apt-get install nomacs
Optional, to remove nomacs, do:
$ sudo apt-get remove nomacs