title: Adding an image inside cell based on cell value
body: <p>I am trying to create a faux progressive checkbox that cycles through 3 states. The default checkbox in Google Sheets seems to only have two states, true or false. I am trying to either edit this to have a third state, and then change the image in the checkbox based on the state, or create my own fake checkbox that adds an appropriate image based on a number in the box (e.g. 1,2 or 3.)</p>
  <p>I am basically a novice with Google Sheets, but I've seen a similar function in other sheets.</p>