Perhaps this was one of the reasons that Richard Thorpe was fired. The part of Dorothy required someone who could play the role with a sense of childish innocence and naivety. Judy Garland was the best option for the job, but even she had to make herself more girlish to be convincing in the role, strapping her breasts down and wearing clothes designed to hide her curves. She was a 16-year-old playing age 12.
For some reason, during early filming, someone thought it would be appropriate to make Garland wear a blonde wig and apply thick make up to her, completely canceling out the actor's own attempts to make herself look younger. Fortunately, someone realized this quite quickly, and decided that she'd be better with her own hair, and a more natural appearance. The scenes were re-shot, although photos like this one remain as evidence that it happened.