Convert .png to .gd2 for Nagios status map

If you ever tried to make Nagios web interface look a little nicer by adding some custom host or service icons, you have probably came across collections of icon packs at Nagios Exchange. You have also noticed an unusual .gd2 extension on some of the images and realized that without this format icons don't display properly on Status Map. I was doing exactly that the other day and couldn't find the icons I needed, so I ended up creating some myself. Here's how to convert a PNG image into .gd2 (GD Graphics Library format).

On Ubuntu install libgd-tools package, it will contain a pngtogd2 app. To convert file.png to file.gd2 use:

$ pngtogd2 file.png file.gd2 0 1

Once you have your .png or .gif and .gd2 images, I tend to use 40x40x8bit images with transparent background, place them in your /usr/local/nagios/share/images/logos/ directory (if you installed Nagios from source) and add these properties to your host or service definition:

define host{
        ...
        icon_image              ubuntu.png
        statusmap_image         ubuntu.gd2
        ...
        }