Although fully-processed astronomical images in FITS format as well as the tools to work with these files are publicly available, neither most educators nor the general public are aware of the existence of these data or how to access them. Through work with secondary school and university undergraduate students, I have developed a series of activities that teach people how they can download astronomical FITS files and perform quantitative analyses with these data. I have written an introduction to using the DS9 image viewer aimed at a very broad audience, and I have also developed several lab scripts, including different versions for secondary school and for university students. These scripts not only teach students about astronomical concepts such as stellar ages and metallicities, the Kennicutt-Schmidt law, and the expansion of the universe but also explain how to make photometric and spectroscopic measurements. These materials are available online as a general teaching resource, and I am continually working to expand the materials available.