Here’s a photograph from the June 20 1933 edition of the Toronto Daily Star, featuring a three-year-old boy with Clark Gable’s smile and Jean Harlow’s hair:
A Google search determined that this caption is inaccurate, as there was no one named Bobby Cook who ever appeared in a movie with Clark Gable and Jean Harlow around 1933.
This is likely a publicity shot for Hold Your Man, which was released a month after this photo appeared. The cast list for this movie includes Bobby Caldwell as the uncredited son of Gable and Harlow’s characters; the little boy in the photo was probably him.
Bobby Caldwell was born in 1928, so he would have been four, not three, when Hold Your Man was filmed. He went on to appear in a total of 14 movies, and was uncredited in all but two of them. His last film was in 1940; he passed away in 1982 at the comparatively young age of 54.