Save a redacted screenshot as PNG, not a mushy JPEG

WhatsApp will crush your carefully barred PNG into a JPEG cousin. You still start from PNG.

JPEG is lossy. Around a hard black edge it can ring. Around a light blur it can leave a ghost of a stem on a digit. PNG keeps the bar as you painted it. Send PNG when the app allows a document. When it does not, send the PNG anyway and let their compressor be the only one.

The format fight is not about which logo looks nicer in a file picker. It is about whether you introduce a second lossy pass before the messenger does, and whether the redaction you see in the editor is the redaction in the bytes you attach.

Why start from PNG if the chat app will recompress anyway?

Because you control the source. A PNG of a solid bar is a uniform region. A JPEG you made yourself of a light blur is already ringing before WhatsApp, iMessage, or Slack take their cut. Two compressors stacked on a smear are how glyphs get an outline. One compressor on a bar is usually an ugly edge, not a readable interior.

If the app has a document or file attachment path, use it. That path often preserves PNG. The camera-roll “photo” path often does not. The sticker path almost never does. Choose the path that treats the file as a file.

What does ringing actually look like on a redaction?

Light and dark fringes along a sharp boundary. On a black rectangle the fringe sits at the edge. The inside can stay empty. On a blur, the “boundary” is the character itself. Compression artifacts can trace the glyph. That is the failure PETS-style leftover structure rhymes with, even when nobody is running an academic recovery: a person staring at the JPEG can sometimes name the digit.

Heavy bars still belong in PNG first. Compare the tools in blur vs bar. If you needed the secret gone, do not pick JPEG as a way to “make the blur look smoother.”

Should you screenshot the screenshot to flatten it?

No. Capturing the editor window a second time with the OS snip can resample again, pick up window chrome, and pick up notifications. Use Download. The download is the flatten. A snip of the browser UI is a new screenshot with a new set of accidents.

The same rule applies to “I’ll just photograph the monitor so the layers are gone.” You added Camera metadata and another optical pass. Flatten in software. GPS is a separate leak: EXIF and GPS.

Is PNG always safe because it is lossless?

Lossless means the pixels you saved are the pixels you get back from that file. It does not mean a translucent highlighter became deletion. It does not mean a PDF text layer went away. It does not mean the messenger will keep PNG. It means you should not add JPEG’s own damage on purpose.

A PNG can still contain a full unredacted image if you exported the wrong layer or never painted the bar. Open the download. Zoom. Then attach that file, not the original.

What if the only send path is a lossy photo bubble?

Send the barred PNG into that path and accept their compressor. Do not pre-export JPEG “to match.” Do not shrink, screenshot, and re-encode three times to hit a size limit. If you must shrink, shrink the PNG in the editor and download once. Keep the original off the thread. Rotate tokens that appeared on screen even under a bar you are not sure survived the bubble.

Email is often kinder to PNG than a chat bubble. A bug tracker that accepts attachments is kinder than a status update that recompresses inline images. Pick the channel that treats the file as a document when the secret was worth barring. If the only channel is the bubble, the bar still has to be real pixels before you drop it in.

BlurThis downloads PNG on purpose so the bar you drew is the bar in the file: download the PNG from this tab.