Elon Musk turns Twitter into 'hotel' for staff
One image shows a room with a double bed, including a wardrobe and slippers.
An ex-worker said new Twitter boss Elon Musk has been staying at the headquarters since he bought the firm, Qazet.az reports.
He last month emailed all Twitter staff saying they "will need to be extremely hardcore" to succeed.
San Francisco's Department of Building Inspection has confirmed it is investigating potential violations following a complaint.
Mr Musk said the city was attacking companies for providing beds to "tired employees".
In a now-deleted tweet, Mr Musk posted that he would work and sleep in the office "until the org is fixed".
The BBC has also been given pictures of sofas at Twitter being used as beds.
Another conference room has an alarm clock, and a picture placed over a made-up bed.