I think 99% of them are phoney and not really them. Posting stuff like that is just asking for trouble. Others that really do do that are vain and just want to try and get attention. Personality means so much more than just looks !
What do you think about girls who have naked or half naked women pictures as their avatars on social websites and etc? (pics may or may not belong to them )
Girls may want to show themselves off to attract admirers or meet boyfriends, they may want to show they have a great life style, particularly if their tanned, false or other wise.
Some maybe fake pictures, some maybe other peoples pictures.
To get a feel of what the person is like, red their bio.
Then make your own mind up whether you wish to befriend them.