How to black out text in a JPEG
Paint opaque black bars over text in a JPEG, then export PNG so the cover is baked in — not a highlighter layer.
How to black out text in a JPEG: paint opaque black rectangles over every digit and name you need gone — in Markup, Paint, Preview, or a browser tab — then save a new file so the cover is baked in, not a highlighter layer sitting on the original.
How to black out text in a JPEG (step by step)
Use Black bar for readable text, especially short numbers. Soft Blur can leave glyph shape on a JPEG that has already been compressed once. Export PNG when you can.
On your phone or computer
iPhone: Photos → Markup. Choose a filled black rectangle (not the highlighter — that is a tint). Cover every digit run with a little padding, then save a copy.
Android: Gallery editor — draw a solid black shape. Light mosaic on a phone number still leaves digit shapes.
Windows / Mac: Paint or Preview Markup with a filled black rectangle. Prefer PNG when you re-export so the bar stays flat after chat recompression.
Or finish in a browser (optional)
Want to do it in a tab with no install? BlurThis is one free option. The file stays on your device. Other browser tools work too if they paint on the page and do not upload the image.
- Open the editor in your browser. No account needed for BlurThis.
- Drop the screenshot, tap Upload from PC or Mobile, or paste with Ctrl / ⌘ + V on a computer.
- Pick Box or Draw. Use Black bar for phone numbers, emails, and OTPs. Use Blur for faces when a soft cover is enough.
- Drag over each private spot. Pinch or use + / − to zoom. Leave a little padding so no letter peeks out.
- Tap Download PNG. Send that file. Keep the original out of the chat or ticket.
Why JPEG makes weak covers worse
JPEG is lossy. Edges around a soft smear pick up ringing when the file is saved again — WhatsApp, email, and many ticket systems re-encode on the way out. A filled black rectangle still survives better than a translucent marker. Prefer PNG for the file you actually send. More on that trade-off in JPEG vs PNG for redacted shots.
What to cover
- Phone numbers, emails, and OTPs in the body or header.
- Card digits, IBANs, and account strings.
- Names on badges, forms, or ID photos in the frame.
- Street numbers and map pins in the background.
- Browser or app chrome that repeats the same secret.
Give each bar a little padding so descenders and the space between digit groups do not peek out. Zoom in. If you can still guess a character, someone else can too.
Highlighter and Markup are not blackout
A yellow marker or a semi-transparent scribble is a tint. Brightness and contrast can bring text back — especially on iPhone Markup. Use a filled shape or a tool that replaces pixels. The Markup brightness problem is the short version of that lesson.
FAQ: Can I edit the JPEG in place?
You can open a .jpg, but save a new export. Keep the unbarred original out of the chat. Do not attach both “by accident.”
FAQ: Is crop enough instead of blackout?
Crop when the secret sits in a corner you do not need. When the text sits in the middle of the UI you must keep, black it out. Crop vs black bar walks both cases.
FAQ: Will chat compression un-hide my bar?
A solid opaque bar baked into the pixels will not “lift.” A light blur or highlighter might still show shape after recompress. Make bars oversized if you know the next hop is JPEG-only.
FAQ: What about text in a scanned document photo?
Same rule: opaque rectangles over every run of digits and names. Check EXIF if the photo came from a camera — redacting pixels does not strip GPS. Screenshots and GPS covers the metadata side.