Best Practices for Maintaining the Integrity of Digital Images and Digital Video
Scientific Working Group on Imaging Technology (SWGIT)
See also the instructional videos on "Crime Scene and Evidence Photography"
Introduction
Integrity ensures that the information presented is complete and unaltered from the time of acquisition until its final disposition. Files which are copied from storage and processed result in new files. These files also must have their integrity maintained. Integrity differs significantly from authentication. Authentication is the process of substantiating that the content is an accurate representation of what it purports to be. For example, authentication of a digital image of a gun on a table could be authenticated by a person at the scene stating the picture fairly and accurately represents the gun on the table. The integrity of the image can be established by methods covered in this document. For further information on image authentication, see SWGIT document “Best Practices for Image Authentication”.
This document is designed to cover the issues that can affect the integrity of digital media files. Extraction of digital media files from devices is not covered in this document.
Integrity of a digital image or video file is best demonstrated through a combination of methods. This document will discuss specific methods and provide examples of how those methods can be applied. Maintaining integrity requires both documentation and security of the files throughout the workflow. A Standard Operating Procedure (SOP) should describe the workflow.