A DICOM file is an image saved in the Digital Imaging and Communications in Medicine (DICOM) format. It contains an image from a medical scan, such as an ultrasound or MRI. DICOM files may also include identification data for patients so that the image is linked to a specific individual.

The DICOM format was developed by the NEMA (National Electrical Manufacturers Association). It was designed for the exchanging and viewing of medical images, such as CT scans, MRIs, and ultrasound images. Various programs for Windows, macOS, and Linux can view DICOM files. These images can also be viewed online with Jack Imaging through certain web browsers. It is only compatible using Chrome, Opera, Firefox, and Internet Explorer with the Google Chrome Frame extension installed. NOTE: DICOM images more commonly use the .DCM extension.