What is the ruling on committed sisters using immodest pictures or pictures of other girls not wearing the legal (Sharia-compliant) attire on their personal profiles on social media?

It is not permissible to display images of women in a way that allows men to view them on social media platforms or elsewhere, regardless of whether the girl posts her own picture or that of another. This is a cause of fitna (temptation/strife), and the Prophet, peace and blessings be upon him, said: "I have not left behind me a fitna more harmful to men than women." The prohibition is further emphasized for alluring pictures or pictures of immoral and immodestly dressed women. Furthermore, photographic imaging has been deemed impermissible, and one should not resort to it except out of necessity or need, and with extreme caution if a woman is compelled to be photographed.