Check out Photoshop guru Bert Monroy artpiece found on the web here.
This is not a photograph. He drew and painted it in Photoshop and Illustrator. The closeup shows amazing and realistic details. It took about 2000 hours to create this piece consisting of over 15000 layers in about 50 files. Even after flattening the image, the file takes up 1.7 GB of disk space.