nomacs 3.22.2 / 3.23.3 Beta

The Windows Photos app is fine until you point it at a folder of camera RAW files, and then you wait.

nomacs opens those same files in about the time it takes to let go of the mouse.

It is free, open source, and it has been the standing recommendation for people replacing a sluggish default viewer for well over a decade.

Stable or Beta - Which One to Download

Two lines are published side by side, and the naming does not make the difference obvious. The short answer is that almost everyone wants the stable one.

The beta is not a preview of some dramatic new interface. It is mostly build-level work - OpenCV 5 compatibility, a move to the KImageFormats plugins on Windows, and updated bundled libraries - so unless one of those words means something to you, the stable line loses you nothing.

What nomacs Actually Does

At heart it is a viewer, not an editor. You point it at a folder, it shows you thumbnails along the bottom, and you move through your images with the arrow keys - that is the whole idea, and nomacs is unusually good at it.

The format list is where it pulls ahead of the built-ins. It reads camera RAW from Canon, Nikon and Sony alongside Adobe PSD files, with nothing to install first.

The Windows build also handles JPEG XL and AVIF, so the newer formats that make File Explorer show a blank grey box simply open. As of 3.22.2 it reads OpenEXR too, which is the format visual effects work arrives in.

It reads images inside ZIP archives and Microsoft Office files, and will extract them to a folder of your choosing. If you have ever unpacked a whole zipped photo set just to check whether it was the right one, that feature pays for itself the first time you use it.

The Feature Nobody Else Has

nomacs can synchronise multiple copies of itself. Open the same image in two windows and they zoom, pan and scroll together; overlay one on the other with adjustable transparency and you can see exactly what changed.

That sounds like a novelty until the day you need it. Photographers compare two exposures of the same frame at 100 percent, architects lay this month's site photo over last month's, and anyone checking whether a compression setting cost them any quality can put the original next to the export and stop guessing.

The synchronisation works across a local network as well as on one machine, which is the part people tend not to believe until they try it.

Does It Open WebP?

Yes - and this question is here because a reviewer hit a build years ago where it did not, which is a fair thing to want settled before downloading anything.

Format support comes from Qt's own image plugins plus the KImageFormats set rather than from anything nomacs writes itself, so the honest answer is that the supported list depends on your build rather than on a marketing page. Fortunately you do not have to take anyone's word for it.

Run nomacs --list-formats from a command prompt and it prints every extension and MIME type the copy on your machine can open. Ten seconds, no guessing, and it settles the question for WebP or anything else you care about.

What the 3.22 Line Brought

3.22.0 was the first non-beta nomacs in quite some time and it was a substantial one. The point releases since have been maintenance - translations, security fixes in the bundled libraries, and the backported OpenEXR support in 3.22.2.

• Colour management. Pick your display profile under Settings and Display, and colours finally look right on a wide-gamut monitor.
• Proper HiDPI rendering - 1:1 pixels at 100 percent zoom. On a 4K laptop screen this is the difference between sharp and "why does this look soft".
• Much better ZIP archive support, rewritten rather than patched.
• Faster, lighter thumbnails, with noticeably less memory and CPU on large folders.
• Improved comments and ratings, CMYK images now open converted to sRGB, and your colour profile survives an edit and save.
• Translations revived, including a new Simplified Chinese one and years of accumulated work imported from CrowdIn.

Under the hood the project is Qt6-only now, and Qt5 support is gone. That matters to you in exactly one way: very old Windows installs are no longer the target, and Windows 10 and 11 are.

Installer or Portable

Both are published. The MSI installer is the straightforward choice and makes deployment across several machines painless.

The portable ZIP unpacks and runs, writing nothing to the registry and leaving nothing to uninstall. It will happily run from a USB stick or sit on a locked-down work laptop where you cannot install anything, so if you want a viewer that leaves no trace, take that one.

Who Should Look Elsewhere

nomacs is a viewer with light editing bolted on - brightness and contrast, rotation, resizing, cropping, false colour and simple collages. That is genuinely enough for most people most days, and if it is not, mixing tools is the sensible answer rather than a compromise.

• Real editing - layers, masks, retouching. That belongs in GIMP, which does most of what Photoshop does for nothing.
• Batch conversion across hundreds of formats. XnConvert is purpose-built for it, and XnView covers over 700 formats if you want browsing in the same window.
• Viewing, editing and slideshows in one polished package. FastStone Image Viewer is the classic pick and has been for years.

How It Compares to the Other Free Viewers

The free Windows viewer field is crowded and, happily, genuinely good. Where nomacs wins is the combination of speed, the synchronisation feature, and RAW plus PSD with no add-ons - but it is not the right answer for everyone.

The full image viewer list has the rest, and if AVIF is what brought you here, our guide to the best AVIF viewers and converters compares them on that one job.

Or Fix the Built-In Viewer Instead

Replacing Photos is not the only option. If the only thing that ever fails is iPhone photos, the missing pieces can be added to Windows itself and everything keeps opening in the app you already use.

The HEIF Image Extensions and HEIC Image Extension add that support to Windows directly.

WIC for HEIC does the same job system-wide rather than per-app, so thumbnails start appearing in File Explorer as well.

Is It Safe?

Yes, and you do not have to take our word for it. nomacs is open source under GPL v3, the code is public, and the developers publish VirusTotal scan results for every Windows binary they ship.

The releases themselves are signed - the tagged commits carry a verified GPG signature from the maintainer who built them, which is a stronger guarantee than a scan result and one most projects this size do not bother with.

There is no bundled adware, no toolbar and no "recommended offers" screen in the installer. It is a volunteer project that has been running since 2011.

What It Runs On

• Windows 10 and 11, 64-bit. The move to Qt6 ended support for older Windows versions.
• Installer and portable builds, both published for every release.
• macOS and Linux builds ship from the same releases, including an AppImage, if you need the same viewer on another machine.
• Free and open source under GPL v3, with no paid tier, no adware and no account.

Quick questions

If your image viewer makes you wait, nomacs will not. It opens RAW and PSD without plugins, reads inside ZIP archives, syncs two windows so you can compare shots properly, and costs nothing - and the screenshots will tell you within seconds whether the interface suits you.

Download nomacs 3.22.2 for Windows, taking the installer for your main machine and the portable build for everything else, or tell us how you got on if you have used it before.