Open .dcm files and convert to JPG
.dcm is the file extension for DICOM Part-10 files — the standard format that hospital imaging equipment writes. CT scanners, MRI machines, digital X-ray units, mammography systems, and ultrasound machines all write .dcm files, which is why imaging CDs from completely different hospitals tend to contain the same confusing folder structure.
Double-clicking a .dcm file on a normal computer either opens nothing or triggers an import prompt from whatever photo app guesses at the format and fails. The format uses 16-bit pixel values, per-file windowing tags, and compressed pixel data variants that standard image software doesn't handle. You need a DICOM-aware tool to see anything useful.
This browser-based converter is a DICOM-aware tool that requires no installation, no account, and no upload. Drop in the .dcm file, see a rendered preview in the correct contrast, choose JPG, and download.
Open the converter — free, no upload
Finding .dcm files on a hospital CD
- On Windows: open File Explorer, navigate to the CD. Look in folders named DICOM, IMAGES, SCANS, or by date.
- On macOS: the CD mounts on the Desktop. Open Finder and browse the same folders.
- Files may have no extension at all — DICOM Part-10 starts with the bytes 'DICM' at offset 128, not by extension.
- If the CD has an DICOMDIR file, that is the index: individual images are in sub-folders next to it.
Questions
The files on my CD have no extension. Are they DICOM?
Probably. DICOM Part-10 files start with 128 null bytes followed by the magic string 'DICM'. This converter accepts files without .dcm extensions — just drop them in and it will detect the format.
My CD also came with a viewer program. Should I use that instead?
Those viewers are often Windows-only and require installation. If you're on macOS, Linux, or a tablet, this converter is easier. If you need the viewer's zoom, measurement or annotation tools for clinical review, use the viewer — for sharing and exporting images, use this.