It's important to understand that although race is one of the most defining factors in the novel, gender is significant as well. As the previous poster explained, white males dominated the cultural idea of "beauty", leading to the popularity of such iconic white females as Shirley Temple. However, this is not singular to the white males. Females of all ethnicities helped perpetuate this stereotype of beauty, as evidenced by the desire of all women in the novel to comform to one of those standards.
There's a hierarchy here, with white males at the the top. They, in turn, oppress and abuse black males. Consider the scene of Cholly's first sexual experience. He and his partner are discovered by two white hunters, who force him at gunpoint to continue, mocking him as he does so. There is a sense that these men have ultimate control over other individuals and their lives. At this time in history, these men could also control who can get a job, a home, where someone could go in public...they truly had the power of authority in society.
Black men, in turn, held power over black women. That is why Pecola suffers so greatly: she lives her entire life at the bottom of this hierarchy of race and gender and class, where the humiliation suffered by her father is forced upon herself and her mother. The scenes of horrific abuse and violence are incredibly visceral expression of this cycle of power. Even Soaphead Church, who exists near the bottom of the social scale himself, holds power over Pecola as an adult male. This is one of the reasons this novel is so powerful: we live through the eyes of the ultimate victim in society.
In Toni Morrison's book "The Bluest Eye" the black females are controlled by the white males ideals of what is considered beautiful. Pecola has a terrible image of herself. She is dark skinned and considers herself to be ugly. Her self esteem is lowered by her ideal that in order to be beautiful she needs to be white.
The black males in Pecola's life have not been a positive influence. Her father rapes her and abuses her. He has power over her life, her body, and this has a negative effect on her self-esteem as well. She is a victim.