When you upload pictures onto a public site (i.e.Facebook) do you relinquish your rights of ownership?

My husband's band has a fan site on Facebook. Recently, the drummer's girlfriend freaked out because my husband used a couple of her photos to make a collage. The pictures used were taken by her and uploaded onto the fan site by her. The collage my husband made was also uploaded onto the same fan page. It seems to me that there's no conflict here and that once you upload photos and videos onto a public site you relinquish any rights. It seems impossible to protect yourself from others using and sharing so there can't be protection. Now she's threatening that there will be hell to pay if anyone uses HER pictures. Thoughts?