No 1939 image could be located.
“…her connection with television dates to an appearance on an experimental Los Angeles channel in 1939. She and her high school classmate sang songs from the light operetta ‘The Merry Widow.’ They were sweltering in a small studio on the sixth floor of the Packard building while the viewing audience gathered in the ground floor auto showroom.”
Excerpt from 2010 Los Angeles Times article: http://goldderby.latimes.com/awards_goldderby/2010/06/betty-white-reflects-on-a-golden-career-.html .
“Even White has a hard time remembering the exact name of her debut show on screen back in 1939. However, there is one particular event she recounts as life-changing during a certain interview with Guinness Book of World Records. She was given the chance to dance on an experimental television show, based in downtown L.A. She wore her high school graduation dress and danced with the student body president (Harry Bennett) of their school: Beverly Hills High – to the tune of ‘Merry Widow Waltz.'”
Excerpt from http://moneyinc.com/things-you-didnt-know-about-betty-white/ .
Learn about 1930s television, including the Don Lee network in Los Angeles, here: https://en.wikipedia.org/wiki/History_of_television#United_States .