What was the ideal female image projected by mass media in the 1950s?
The ideal female in the fifties was a stay-at-home mom who ran her household effortlessly, had milk and cookies for her children when they came home from school, made perfect meals, and was, if not submissive, then at least deferential to her husband, who was in all ways the head of the household. She exhibited very little sexuality because it was her husband's satisfaction that was important, and besides, husbands and wives were shown sleeping in twin beds, not together. These women were always portrayed as dressing modestly. Women were not generally college-educated, and if they were, it was only for the purpose of meeting prospective husbands and/or to make them better wives. They were not expected to pursue careers. Generally, the only acceptable work outside the home was volunteer work.
Some television shows that portrayed women like this were Leave It to Beaver, I Remember Mama, and Father Knows Best. The only program that went against these stereotypes in any way was I Love Lucy, because at least Lucy presented as an "imperfect" wife in some ways.
I assume that you are asking about the all-around image of an ideal woman, not simply about the physical aspects of an ideal woman. If so, the major aspect of the ideal female image of the 1950s was domesticity. The ideal woman very much identified with motherhood and being a housewife.
In the 1950s, the ideal woman had to be married. She had been trained since childhood to be a good housewife, perhaps through such things as participation in the Future Homemakers of America club in high school. She was portrayed as a woman who stayed home, took care of the children, and supported her husband. She was not a woman who hungered for a career or for achievement on her own.
This view of the ideal woman in the 1950s led to a feeling of frustration among many women and can be credited with helping to lead to the women's rights movement that would start in the 1960s.