Skip to main content

Your Windows 11 screenshots may not be as private as you thought

When you capture a screenshot and crop out sensitive information, it’s still possible to recover a portion of the image that was supposedly removed in some circumstances.

This isn’t the first time redacted documents have turned out to have left hidden data intact and readable with the right tools and knowledge. A recent bug in Google’s Markup tool for the Pixel phone, humorously dubbed the “Acropalypse,” shows this issue might be surprisingly common.

In a comment on the tweet about the Pixel bug, Chris Blume shared a similar discovery about the Windows Snipping Tool. A PNG image that requires 198 bytes grows to a much larger 4.7kB file when saved over an existing image. When saved as a new file, it increases by only 56 bytes, probably adding some metadata.

I've got a fun one for you all to look at.

I opened a 198 byte PNG with Microsoft's Snipping Tool, chose "Save As" to overwrite a different PNG file (no editing), and saves a 4,762 byte file with all that extra after the PNG IEND chunk.

Sounds similar :D

— Chris Blume (@ProgramMax) March 21, 2023

The implication is that Windows Snipping Tool overwrites files without reallocating storage. Instead, the new image data overwrites the existing file, followed by an end-of-file marker, and the rest of the old content remains.

While this might not sound like a common occurrence, consider the scenario Bleeping Computer described. You take a screenshot with the Windows Snipping Tool and save it. Realizing some sensitive data is visible, you crop it out and save over the original file.

In a Windows File Explorer preview pane and the Photos app, it looks like the crop is successful. In truth, the file size will be the same as that of the uncropped version, and parts of the old image are still there.

It isn’t easy to see the old data, but not that hard if you are looking for it and have some developer tools or a specialized app made to take advantage of this vulnerability.

Microsoft is aware of the issue and is currently investigating. In the meantime, you can protect yourself by cropping with the Photos app or other Windows photo editor. You can keep using the Snipping Tool safely if you save cropped screenshots as new files instead of overwriting existing data.

Editors' Recommendations

Alan Truly
Computing Writer
Alan is a Computing Writer living in Nova Scotia, Canada. A tech-enthusiast since his youth, Alan stays current on what is…
This new Windows 11 shortcut made using my PC so much easier
The Digital Trends website on the KTC G42P5.

Microsoft is constantly adding new features to Windows 11, and it's easy for small quality-of-life updates to get buried under Bing Chat integrations and Windows Copilot. I discovered one such feature in the Windows 11 23H2 update a couple of weeks ago, and it's a simple shortcut: Ctrl + Win + V. 

Using this keyboard combination will pull up the new-and-improved volume mixer is Windows 11's latest feature update. It's been a massive time save for me, and if you use your PC in a similar way to how I use mine, it'll likely save a lot of time for you, too.

Read more
Windows 11 may replace a favorite shortcut with more AI
Windows 10 desktop showing task view.

Microsoft is currently testing removing a popular Windows 11 feature and swapping it out for AI.

The brand recently rolled out the Windows 11 preview build for the Dev Channel. In the build, the shortcut to Copilot is a primary feature of the operating system. The shortcut will be located in the bottom-right corner of the screen and will replace the "Show desktop" button, which has been commonplace on Windows since 2009, according to Neowin.

Read more
Windows 11 might finally reverse course on preinstalled applications
Windows 11 set up on a computer.

Microsoft is testing the ability to allow users to uninstall various preinstalled applications from its operating systems to make way for third-party apps and modern updates of older programs.

The brand recently began rolling out Windows 11 Insider Preview Build 23585, which will allow applicable users to uninstall a range of apps from Windows 10 and Windows 11. Microsoft detailed on its Windows Insider Blog that the Insider Preview Build update will allow users to uninstall the Camera app, Cortana, Photos app, People app, and Remote Desktop (MSTSC) client without needing extra tools.

Read more