It's never been stated if the pictures were digital, on the phone, or on a camera, or prints. I suspect the pictures were on the phone because there's been no mention that she had anything other than a cell phone when she escaped from the house. To have prints, she would have had to have access to a printer, and that would be risky...........taking pictures with a cell phone or camera and then printing them out on a printer. I'm guessing there was a printer in the home as LT had a Facebook page, so likely a computer and some sort of printer.
My guess is that the 17-year-old probably had a simple flip-phone, something easy to conceal in the house, and easy to conceal when she escaped.
If we can assume housekeeping habits were the usual, concealing anything should be pretty easy. They weren't kept in prison cells with nothing except security cameras on them as far as I know. Making some noise is possible, especially when the shopaholic is out shopping.