A judge said that teenage girls acted in tandem to carry out the "cowardly attack" on vulnerable Angela Wrightson.
Handing them life sentences at Leeds Crown Court, Mr Justice Globe said: "It was an attack that included gratuitous degradation."
The girls, aged 13 and 14 at the time of the murder, took selfies of themselves with their victim cowering in the background with marks showing on her face.
The girls also shared a photograph on social media of them in the back of a police van saying: "...in the back of a bizzie [police] van again."
This was a sustained attack over a long period of time carried out with weapons in many different ways.
"She undoubtedly suffered considerably, both mentally and physically, before she ultimately lost consciousness and died.
"Her alcoholic state, considerable though it was, may have numbed the pain but I stress the word may and it most certainly would not have taken it away."
The girls, who cannot be named for legal reasons, will attend Leeds Crown Court for sentencing later today.
Angela Wrightson was a frail and highly vulnerable woman. She had lived what has been described as 'a torrid life.'
Two teenage girls have been found guilty at Leeds Crown Court of murdering 39-year-old Angela Wrightson in her Hartlepool home.