Newbie trying to build first survey using Survey Project 2.0 (new admin password didn't seem to work on 2.1)

I'm trying to build a web survey for use on touchscreen kiosk style browser for elderly people with poor eyesight. So I want to replace tiny radio button with smiley / unhappy icons about 150 pixels square. I can insert these as images easily, but to select the answer touching the image won't work, you have to touch the tiny radio button to one side. If I could access the answer html directly I could probably fix this, but I can't work out how to get there.

Any help appreciated