If you haven’t noticed yet the Raspbian download page on raspberrypi.org has a nifty new operating system image to check out, Raspbian Jessie Lite! The lite version of Raspbian Jessie is just like the normal Raspbian Jessie operating system but without any of the graphical desktop environment packages. This means it’s much, much smaller than the normal image–it’s only about 1.3 gigabytes in size vs. over 4 gigabytes for the normal image!
You can see more details about what’s included in Raspbian Jessie Lite in this forum thread, but from what we’ve seen it has almost everything you need for a simple headless Raspberry Pi Project. Programs like Python 2.7 and wpa_supplicant (for WiFi networking) are included, and any other Raspbian package is just an apt-get install away. Remember you won’t be able to boot to the desktop and run graphical programs, but for a lot of little Pi applications this is no problem. This new Raspbian Jessie Lite image is perfect for the Pi Zero too!