A unique identifying number assigned to the image.

Example: 200904001

This number is the same as the 9-digit accession number we give an image when we scan or photograph it.

The first four digits are the year the image was scanned.

The fifth and sixth digits are the month in which the image was scanned.

The final three digits are sequentially given to the images in the order in which they were scanned.

YYYYMM###