Use a still frame elsewhere

I want to take a still frame from an iMovie project and use it in another, non-iMovie, project. I find the frame I want in the event browser, right click it, and select Add Still Frame to Project. My selected still appears at the end of the video on the story board. Now what? I cannot drag it to a non-iMovie folder and cannot copy/paste it to the non-iMovie folder. Right clicking the still does not present Reveal in Finder as suggested in the book I bought. Thank you