Which image formats can nomacs open?

nomacs opens all common image formats, and it explicitly supports RAW and PSD files. That makes it a reasonable choice if you regularly deal with a mix of everyday photos, camera raw files, and layered Photoshop documents, and you want one viewer instead of several. The details below come from the project's own site (nomacs.org), so treat "common formats" as the site's wording rather than an exhaustive list.

What the project states

The nomacs homepage describes it as "a free, open source image viewer, which supports multiple platforms," and says you can use it "for viewing all common image formats including RAW and psd images." The feature sections on the same page reinforce this:

So the format question is answered at a category level: common formats, plus RAW and PSD called out by name.

What "common image formats" covers in practice

The site does not publish a format-by-format list, so the honest answer is that the exact set depends on the build and the underlying image libraries it uses. In practical terms, "common formats" normally means the everyday set you would expect any viewer to handle — the kind of files produced by phones, screenshots, and web downloads. If your workflow is built around those, nomacs is very likely to open them.

The two formats worth noting are the ones the site names explicitly:

• RAW — camera raw files, which many simple viewers cannot display at all. nomacs lists RAW support in both the summary and the "Image viewing" section.
• PSD — Photoshop documents. These are also named directly, which matters because layered PSD files are frequently unsupported elsewhere.

If your library is mostly RAW or PSD, that explicit mention is the strongest signal on the page.

How to confirm a specific format before committing

Because no complete list is published, verify against your own files rather than assuming:

1. Download nomacs from the official site (nomacs.org) or its GitHub releases page.
2. Open one representative file of each format you care about — for example one RAW from your camera and one layered PSD.
3. Check that it renders correctly, not just that it opens. For PSD, confirm whether layers appear as expected for your use.
4. If a format fails, note the exact extension and file source, since support can vary by how the file was written.

The expected result is that common formats, RAW, and PSD display; anything outside that set is unverified until you test it.

Common sticking points

• "Common formats" is not a guarantee. It is the site's phrasing, not a published compatibility matrix. Treat unusual or proprietary extensions as untested.
• RAW is not one format. Different camera makers use different raw variants, so a RAW file from one brand may behave differently from another. Test with your own camera's files.
• PSD rendering can differ from Photoshop. A viewer showing a PSD is not the same as Photoshop showing it; check whether the layers and adjustments you rely on are preserved.
• Build and platform matter. nomacs supports multiple platforms, and format handling can depend on the libraries bundled with a given build, so a file that works in one install may not in another.

Who this fits

nomacs suits you if you need to view a varied image collection — ordinary photos alongside RAW captures and PSD files — in a single free, open-source viewer, and you are willing to confirm your specific formats by testing. It is licensed under the GNU General Public License v3.0, and the site lists a current version of v3.22.0 with links to GitHub, Matrix, Docs, and a blog. If your needs center on one unusual format, verify that format first; if they center on the common set plus RAW and PSD, the project's stated support covers you.