Sketch snapshots
Originally posted on the
Sketchpad blog 
Excerpt:
If you’ve been making your sketches in the Studio, you may have noticed a new camera icon in the top-right corner of your canvas. Clicking this little camera will take a snapshot of your sketch that can be used in a few different places. When a canvas is not running, your snapshot will act as a preview of what’s to come. Clicking the button still brings it to life, but now you have a sense of what that may do.