You might have to grab the bottom left hand corner of the new window to expand the window to see your results. Determine the diameter for several sunspots. The first tool in the right hand column of the tool window is used to drag out rectangular areas. The second tool in the right hand column of the tool window is used to define oval or circular areas. Using the third tool in the right hand column of the tool window, you can connect a sequence of points with line segments, creating a polygon of your own design.
Sunspots have two components - a dark inner penumbra and a lighter outer umbra.
Divide up into several NASA imaging teams. The above process will work on ANY image that you find on the Internet. Try out the following to demonstrate your skills at image processing. Find a map of your state, calibrate the image using the map scale, and measure the distance by road between the two places. Use the known diameter of Jupiter to calibrate your image.