Here's how you can install the Nomacs 1.2.0 image viewer in Ubuntu 13.04. Nomacs is a free open source image viewer that supports JPEG, PNG, GIF and other file formats.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
sudo add-apt-repository ppa:nomacs/stable
sudo apt-get update
sudo apt-get install nomacs
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