Microsoft has rolled out a new AI photo-editing feature called Relight for the Windows 11 Photos app, but only on the latest Copilot+ PCs. The tool, first spotted in an Insider build in mid-2024 and now broadly available with Windows 11 version 24H2, lets you add, remove, or reposition virtual light sources in any image—all driven by the dedicated Neural Processing Unit (NPU) on Snapdragon X-powered devices.

What Actually Changed

Relight lives inside the Photos app version 2024.11080.4001.0 or later. Launching the feature presents a horizontal slider that pans a virtual light around the subject, with a secondary slider for brightness or intensity. Behind the scenes, a machine learning model running on the NPU estimates the 3D geometry of the scene—faces, objects, backgrounds—and re-lights the image in near real time, preserving textures and colors that older manual dodge-and-burn techniques would wreck.

The update didn’t require an entirely new app. Microsoft quietly refreshed the existing Photos via a Microsoft Store update in early September 2024, alongside a broader Copilot+ rollout on Qualcomm’s Snapdragon X Elite and X Plus platforms. Intel and AMD Copilot+ PCs won’t get the feature until their NPUs ship with the required AI models, expected in late 2025.

Three controls matter:
- Light direction: Drag the virtual sun anywhere along a 360° ring.
- Intensity: 0–125% scale, with 100% as the original ambient light level.
- Falloff: A softness dial that broadens or narrows the light cone, mimicking a diffuse umbrella or a hard spotlight.

What It Means for You

For everyday users stuck with ceiling glare turning their portrait into a zombie mugshot, Relight is an instant fix. You open a photo in Photos, hit the edit button, choose “Relight,” and drag the light to a flattering position. No need to understand histogram manipulation or layers. The output saves as a new JPEG, preserving the original.

Power users and imaging enthusiasts will notice the tool doesn’t replace Photoshop’s advanced relighting, but it does what smartphone apps like Google Photos’ “Portfolio” could only dream of: it re-lights the actual image, not just applies a filter. However, it works only on stills, not video. The NPU offload means zero fan noise and under-3-second processing on a 24MP file, something Intel-based AI routines still can’t match without a discrete GPU.

IT administrators need to know the feature is on by default in Windows 11 Home and Pro, but can be disabled via Group Policy or Microsoft Intune if data sovereignty concerns arise—the AI model runs entirely on-device, so no cloud upload happens. The policy controls are under “Computer Configuration \ Administrative Templates \ Windows Components \ Photos\ Allow Relight. If your fleet includes devices without an NPU, the toggle simply won’t appear, so there’s nothing to accidentally click.

Developers: the underlying NPU APIs are part of Windows Copilot Runtime, so third-party apps could theoretically call similar relight models. The official model is a RestrictedExecution model that only the Photos app can invoke now, but Microsoft has hinted at open access by Build 2025.

How We Got Here

AI relighting isn’t new. Adobe showed Project Glasswing at Adobe MAX 2021, Nvidia’s Canvas does landscape relighting, and Luminar Neo has had its Relight AI slider since 2022. What’s different is Microsoft baking it directly into the default photo viewer on Windows—a stranglehold no third-party uses.

The journey started with the Windows Copilot+ platform announcement in May 2024, where Microsoft promised “Windows Studio Effects” and “Recall,” but also teased “advanced photo editing” using the NPU. The first build to leak with Relight appeared in July 2024 under KB5039212 (Windows 11 Insider Preview Build 26120.xxx). Enthusiasts on Windows Central’s forum dissected the XML strings, but the feature remained inactive until the 24H2 public launch on September 26, 2024. By October, Microsoft Stores were pre-loading it on Surface Pro 11 and Surface Laptop 7. AMD’s Strix Point and Intel’s Lunar Lake laptops, announced at Computex 2024, promised similar NPU capabilities but have yet to ship with the necessary driver stack.

Under the hood, Relight relies on a modified Stable Diffusion unet, trained on synthetic relighting data pairs, optimized to INT8 precision for the NPU. The model size is about 450 MB, downloaded on demand when you first open the feature.

What to Do Now

If you own a Copilot+ PC:
1. Check your Windows version by pressing Win+R, typing winver. It should read “Version 24H2 (OS Build 26100.xxx)”.
2. Open Microsoft Store, click Library, and update Photos to version 2024.11080.4001.0 or later.
3. Open any photo (JPEG, PNG, HEIC) from File Explorer; it should default to Photos.
4. Click “Edit image” (Ctrl+E), then the “Light” tab, and select “Relight.” If the tab doesn’t show, your NPU driver may be outdated—run Windows Update and check optional updates for “Qualcomm NPU driver.”
5. Drag the light direction ring and adjust intensity. Use the falloff slider for dramatic side-lighting effects.

For non-Copilot+ PCs, including current Intel and AMD laptops: there’s no workaround. The feature directly requires the NPU, and emulation on CPU/GPU is not allowed. If you’re planning a purchase, wait for “Copilot+ PC” branding with at least 40 TOPS NPU throughput (Snapdragon X models all qualify).

IT admins should test Relight with a small group of Copilot+ devices before broad deployment. Group Policy template photos.admx version 24H2 v2 adds the necessary policy. Disable it if your sector’s compliance rules forbid any on-device AI manipulation of images, though the data never leaves the device.

Outlook

The next twist will arrive with the spring 2025 Windows update, codenamed “Hudson Valley.” Microsoft is expected to expand the relight model to handle multiple light sources simultaneously, let you save light profiles, and—most interestingly—run on Intel’s Lunar Lake and AMD’s Strix Point NPUs. Industry chatter from a Qualcomm summit in December 2024 suggests a future video-relight engine is in development, but that will require a 60+ TOPS NPU, likely arriving with Snapdragon X gen 2 in 2026. For now, the button is real, it works exclusively on Copilot+ PCs, and it turns anyone with an NPU into a quick-fix lighting director.