The bitmap extension is pre-installed in NetLogo. For instructions on using it, or for more information about NetLogo extensions, see the NetLogo User Manual.
The Bitmap Extension allows you to manipulate and import images into the drawing and patches. It offers features not provided by the NetLogo core primitives, such as: scaling, manipulation of different color channels, and width and height reporters.
To import and manipulate images you will need to include the bitmap extension in your NetLogo model.
extensions[ bitmap ]
The image file formats supported are determined by your Java virtual machine's imageio library. Typically this is PNG, JPG, GIF, and BMP. PNG is a good, standard choice that is likely to work everywhere.
If the image format supports transparency (alpha), that information will be imported as well.