The photograph below shows typical women's fashions of the 1920s: library of congress lc-b2- 6504-8 [p& p] what made this style of fashion controversial on the 1920s?

No photograph can be seen on my device; I can only offer an educated guess.
Prior to the 1920's women's fashion was extremely conservative and covered as much bare skin as possible. So much so that even sleeveless dresses were not found due to the stigma they would bring to the wearer. Some fashion styles that debuted in the 1920's were against this tradition (ie: flappers, bathing suits). The controversy surrounding these fashion trends was relative to the exposure of bare skin rarely seen prior and which carried a negative stigma in society.