Photo editors for Linux, and what each one is for.

“Photo editor” covers three kinds of program, and most of the confusion comes from mixing them up.

A RAW developer turns the raw data from your camera into a photograph without ever changing the file: exposure, colour, lens corrections and local adjustments are kept as instructions. darktable, RawTherapee, ART, RapidRAW and Numa are RAW developers.

A photo manager keeps a large collection in order, with tags, faces, places and search, and usually has a simpler editor. digiKam is one.

A pixel editor works on the picture itself, in layers: retouching, compositing, text. That is GIMP, and Krita for painting. Many photographers use one of each: they develop in a RAW developer and finish the odd picture in GIMP.

digiKam and GIMP are left out of this table because they are not RAW developers; digiKam’s Image Quality Scanner does sort a collection by blur, noise, exposure and compression.

The most complete open-source RAW developer, developed on Linux first and around since 2009. It has a very large set of modules, a scene-referred pipeline, drawn, parametric and raster masks, Lua scripting, tethering and printing, and it can use the graphics card. Version 5.6 added local AI tools: click on an object to mask it, AI denoise and upscaling, all optional and run on your computer. The price of that depth is a steep first week. It suits people who want every control. darktable.org

RawTherapee gives very fine control over demosaicing, sharpening, noise and colour, and its camera profiles are used well beyond it. It works on your folders through a file browser rather than a catalogue. rawtherapee.com

ART is Alberto Griggio’s fork of RawTherapee, with fewer settings and a simpler interface. Local edits are layers, each with a parametric, colour, drawn or brush mask, and it can hand work to external AI tools. ART

A newer RAW developer, and the closest to Numa in what it sets out to do: it works on your folders, finds subject and sky masks, spots blurred frames and duplicates, and runs its pipeline on the graphics card. It also does things Numa does not: tethering, HDR merge, panoramas, depth masks and generative remove, all run on your computer. It is on Flathub. Its interface is a web view rather than a native toolkit. RapidRAW on GitHub

KDE’s photo manager, and the one for a very large collection: folders indexed in a database, tags, places, metadata, batch work, and faces found and recognised across the whole collection. Its Image Quality Scanner can sort a collection by blur, noise, exposure and compression. Its editor works on pixels and opens raw files, or hands them to darktable or RawTherapee; it is not a RAW developer with masks. digikam.org

GIMP is the best-known free photo editor on Linux, and the right tool for work on the picture itself: layers, selections, retouching, compositing and text. Since GIMP 3 its filters can stay editable. It has no RAW developer of its own: a raw file opens through darktable or RawTherapee. gimp.org

Krita is made for painting and drawing. It can edit a photograph, but that is not what it is for. krita.org

A RAW developer and library for Linux, written in Rust as a native GTK 4 and libadwaita app. A library is a folder you already have: there is no import step, and Numa never writes to your originals. Culling measures each frame: sharpness, blown highlights on the raw data, bursts, closed eyes, and a suggested rating with its reason, which never overwrites yours. Masks are found by kind for what is in the frame, by models that run on your computer, and you can click on anything else to select it. Numa imports presets from Lightroom and Capture One, reads LUTs, and exports JPEG, JPEG XL, AVIF, 16-bit TIFF and DNG.

It is made to be simple by default without leaving things out: a slider you have not touched is just a name and a value, each section starts with the one control most edits need, and there is no separate “pro” mode to switch to. Numa for iPhone, iPad and Mac is a separate app with the same controls; its TestFlight beta opens once Apple’s review is done.

Numa’s code is written by Claude, an AI model by Anthropic, working from my feedback as a photographer: comparisons with other RAW developers and with the camera’s own JPEGs, and reports of what looks wrong. The decisions and measurements are written down in the repository, and more than 600 automated tests run on every push, with one camera file per make.

Numa uses RawTherapee’s DCP camera profiles, and RealPLKSR, the upscaler darktable chose and converted. Numa for Linux: install and features

• It is young: the first release was on 15 September 2026, and it is made by one developer.
• It is tested end to end on Fujifilm and Sony raw files. Files from other cameras open, but have had less testing.
• It is not on Flathub or in any distribution, and it runs on 64-bit Intel and AMD only: no ARM, no Windows.
• Its develop pipeline runs on the processor; darktable and RapidRAW can use the graphics card.
• It has no layers (GIMP), no tethering or printing (darktable), and no catalogue tools on digiKam’s scale.
• RapidRAW does much of what Numa does, and more: tethering, HDR merge, panoramas and generative remove. It is on Flathub.
• darktable 5.6 has AI tools of its own: object masks, denoise and upscaling.

• Retouching, compositing, text, work in layers: GIMP.
• A very large collection, metadata, faces across it, batch work: digiKam.
• The deepest control over a raw file, and years of testing on many cameras: darktable or RawTherapee; ART for RawTherapee made simpler.
• AI masks in an app from Flathub: RapidRAW; darktable 5.6 has AI object masks too, but in its own builds, such as its AppImage, not the Flathub one.
• A native GNOME app that stays simple, culling that measures, masks found by kind, libraries that are plain folders, presets from Lightroom and Capture One: Numa.

• Numa for Linux
• A Lightroom alternative
• Try Numa’s sliders in your browser