Sometimes a common consumer-level digital camera will work.
I was able to do this in a pinch when a presenter at a small workshop only brought color printouts of the photos he wanted to share with the audience. Instead of having him pass around the photos to the attendees, I took out my camera and quickly snapped a full-frame shot of each one. I then slipped the memory card into my laptop, copied them over, and displayed the photos in a slide show on the room's projector. I was surprised at the fine quality of the results.