Hi D,
Thanks for posting this. Here's how to show the correct/incorrect indicator (there's a quick answer early, with a longer explanation for using custom images that follows) -
https://share.suddenlysmart.com/public/support/radiobutton-checkbox-show-correct-incorrect-indicators.mp4Basically, you need to set the correct/incorrect indicator (it's sort of like the button icons) in the Properties panel for the Radio Button object.
Hope that helps!