You are required to take photos of the vehicle at the start and end of the rental period. These photos will be used to prove the condition of the vehicle in the case of an incident report. Please check that your camera accurately retains the time and date the photo was taken (metadata).
Photos must be clear, well illuminated, in focus, and high resolution. A smartphone camera should do a sufficient job.
Important things to photograph are the dashboard (fuel gauge), windscreen, interior and exterior of the vehicle, and any existing damage.