How to redact a screenshot
Before you post a screenshot of a chat, an email or a banking app, cover what shouldn't be seen with solid black. Here's why blur and highlighter pens aren't enough, and how to do it properly.
Open the redaction tool Free, no account. The file stays on your device.Quick steps
- Open maskyourdocs and choose the screenshot or photo.
- Drag a box over each name, number or message to hide.
- Press Export, then Generate.
- Download the image. The covered areas are solid black in the pixels.
Why blur and pixelation aren't safe
- Pixelation can be reversed. Tools exist that rebuild pixelated text by trying fonts and characters until the blocks match.
- Blur leaves shapes behind. For short values like a PIN or the digits of a card number, there are few enough possibilities to guess by comparison.
- Highlighter pens are see-through. A black highlighter stroke from a phone's markup tool can let the text show through when someone raises the brightness and contrast.
Solid, opaque black is the only cover that leaves nothing behind.
Edited images can keep more than you see
In 2023, a bug nicknamed "aCropalypse" was found in Google Pixel's Markup tool, and the same flaw turned up in the Windows 11 Snipping Tool and Snip & Sketch on Windows 10: some cropped screenshots still held parts of the original image. They've been patched, but they show why a freshly encoded image is safer than an edited one.
Photos also carry metadata: the camera, the time and often the GPS location. maskyourdocs paints your boxes onto a fresh copy of the image and encodes it from scratch, so neither leftovers nor metadata come along.
What to check in a screenshot
- Names and profile pictures in chat headers
- Phone numbers and email addresses
- Notification banners at the top of the screen
- Balances, card numbers and account numbers
- Browser tabs, the address bar and bookmarks
- QR codes and barcodes, such as on tickets and boarding passes
Step by step
Step 1: Open the image
Go to maskyourdocs, press Choose a file and pick the image. PNG, JPEG, WebP, AVIF, GIF and HEIC work wherever your browser can open them. If it can't (some browsers can't open HEIC), the tool says so; save the image as JPEG or PNG and try again.
Step 2: Draw a box over each detail
With a mouse, drag to draw. On a phone or tablet, rest a finger on the spot until a ring appears, then drag. A quick swipe still scrolls, and two fingers pinch to zoom. Tap or click a box to move it, resize it from the corners, or remove it. Cover a little more than the text itself.
Step 3: Export
Press Export, then Generate. The image is exported at its original resolution with the boxes painted into the pixels. The tool then reads the new image back and checks that every box is solid black. A very large image may be scaled down to fit the browser's limit, and the result says so.
Step 4: Download
Press Download. The copy's name starts with maskyourdocs.com-, so you can tell it from the original. A JPEG comes back as a JPEG; every other format comes back as a PNG.
Questions
Is blurring a screenshot safe?
Not reliably. Pixelated text can sometimes be rebuilt, and short values like digits can be guessed from a blur. Use solid black boxes.
Does redacting remove location data from a photo?
Yes. The exported image is encoded from scratch, so metadata such as GPS location, camera model and time is not carried over.
Why did my HEIC or WebP image come back as a PNG?
Only JPEGs are exported as JPEG. Every other format is exported as PNG, which every app can open.
Can I redact several screenshots at once?
No, one image at a time.