using images for choices

I am still learning notes and I have a feeling this is quite easy, but can't figure it out...
I am creating a status report form of such and want the user to be able to click on the status of his work: green, yellow, or red.
Ideally, I would like to use a radio button but would like the choices represented by a green dot, yellow dot, and red dot.  
Another idea if the radio button doesn't work: have a green button, red button, and yellow button, and when one of those buttons is "clicked" it fields in the corresponding text ("Green", "yellow" or "red) into a text field, perhaps the text can then even be displayed in the correct color - green for "green", etc.

Also, in the view, I would like the status field to be displayed as an image as well (green dot, red dot, or yellow dot, and not just text).
I am not sure how to code this though.