GIMP is a free, open-source image editor for Windows, macOS and Linux. Dental teams use it to crop, adjust and annotate X-ray images and clinical photos for teaching, case presentations and publications. It is an image editor, not a medical viewer, but it can open some DICOM files directly.
If you searched for “GIMP DICOM” or a GIMP DICOM plugin: no separate medical plugin is needed, and no official “medical plugins” package exists. GIMP ships with a built-in DICOM import and export plug-in (file-dicom). It opens single, uncompressed DICOM images and can save images as DICOM. Knowing its limits, described below, will save you time.
GIMP at a glance
| Item | Details |
|---|---|
| Latest version | 3.2.6 (10 September 2026) |
| Licence | Free and open source, GNU GPL |
| Platforms | Windows 10 (1903) or later, x86-64 and ARM64; macOS 11 Big Sur or later, Apple Silicon and Intel; Linux (AppImage, Flatpak, Snap) |
| Developer | The GIMP Team (volunteer open-source project) |
| Official website | gimp.org |
| Best for | Preparing and annotating dental images for teaching, slides and papers |
What it does
- Opens .dcm and .dicom files with the built-in file-dicom plug-in, which recognises files by the DICM signature.
- Reads uncompressed DICOM: implicit and explicit VR little endian, deflated explicit VR little endian, and the retired big-endian syntax.
- Loads 8-bit and 16-bit greyscale and RGB images. 16-bit data are reduced to 8 bits per channel on import.
- Keeps the original DICOM header elements with the image and writes them back when you export to DICOM again.
- Exports greyscale or RGB images as uncompressed DICOM; images that did not come from DICOM get mandatory tags filled with placeholder values.
- Full editing toolset: crop, rotate, levels, curves, sharpening, layers, text, paths and arrows for annotation.
- Exports to PNG, JPEG, TIFF, PDF and many other formats for slides and publications.
How dental teams use it
Preparing an X-ray figure for a lecture or paper
- In your imaging software, export the image as PNG or TIFF (or as uncompressed DICOM).
- Open it in GIMP and crop away any burned-in patient name or date.
- Use Colors, Levels or Curves to improve contrast for projection.
- Add labels and arrows on separate layers, then export as PNG for slides or TIFF for print.
Opening a single DICOM file a colleague sent
- Use File, Open and select the .dcm file.
- If GIMP reports that the transfer syntax is not supported, the file is compressed. Open it in a DICOM viewer such as Weasis and export a PNG or TIFF instead.
- Remember that 16-bit data are cut to 8 bits, so fine grey-level detail can be lost. Adjust window/level in a DICOM viewer before exporting when detail matters.
Anonymising images before sharing
Export to PNG or JPEG rather than DICOM. A DICOM file that GIMP opens and saves again keeps the original header, including patient name and ID.
Install and first run
- Windows: run the installer (Windows 10 version 1903 or later, x86-64 or ARM64). The Microsoft Store version requires Windows 11 or Windows Server 2022.
- macOS: use the build for your processor (Apple Silicon or Intel), macOS 11 or later. The GIMP team does not publish GIMP on the Mac App Store; listings there come from third parties.
- Linux: AppImage (for Debian 13 or newer distributions), Flathub or the Snap Store; Flatpak and Snap receive automatic updates.
- First DICOM file: no plug-in installation is needed; File, Open accepts .dcm files straight away.
- Gotcha: multi-frame files, such as CBCT volumes stored as one file, open as a single image. GIMP cannot scroll through slices.
Limitations
- Not a DICOM viewer: no series handling, no CBCT slice navigation, MPR or 3D.
- Compressed DICOM (JPEG, JPEG 2000, JPEG-LS, RLE) cannot be opened.
- No DICOM window/level presets; 16-bit images are reduced to 8 bits.
- Measurements are in pixels; DICOM pixel spacing is not used, so there are no calibrated millimetre readings.
- Edited images are not suitable for diagnosis, and GIMP is not medical software.
GIMP vs alternatives
For viewing DICOM, use a real viewer. Weasis is free on all three desktop platforms, opens compressed DICOM and CBCT volumes, and exports PNG, JPEG or TIFF for editing in GIMP afterwards. RadiAnt DICOM Viewer (Windows, shareware) is quick for copying a view straight into slides. Horos does the same job for free on a Mac. GIMP’s strength is the step after viewing: cleaning up, annotating and laying out images.
FAQ
Can GIMP open DICOM files?
Yes, if the file holds a single, uncompressed image. GIMP’s built-in DICOM plug-in handles .dcm and .dicom files; compressed files are rejected.
Is there a GIMP DICOM plugin I need to install?
No. DICOM support is part of the standard GIMP installation. There is no official separate medical plugin pack.
Why does GIMP say the transfer syntax is not supported?
The DICOM file uses compression, such as JPEG or JPEG 2000, which GIMP cannot read. Export the image from a DICOM viewer as PNG or TIFF.
Can GIMP be used as a DICOM viewer?
Only for single images. It cannot display series, CBCT volumes or calibrated measurements; use Weasis, Horos or RadiAnt for that.
Can GIMP save as DICOM?
Yes. It exports greyscale and RGB images as uncompressed DICOM, but the header contains placeholder values unless the image came from a DICOM file.
Is GIMP free?
Yes. GIMP is free and open source under the GNU GPL, with no paid edition.
What is a free alternative for opening DICOM?
Weasis is free and open source and handles compressed DICOM, CBCT volumes and measurements properly.
Last checked against official sources: 26 September 2026 (developer website: gimp.org). Versions and licence terms change — confirm on the developer's site before deploying in a clinic.
