What a screenshot gives away

1 Look along the edges

• Notifications — who wrote, and the first line of what they wrote.
• Tabs, bookmarks and the address bar — what else you had open, and links that carry your account or an order number.
• Your name or photo in a corner, the network's name, the battery and the time.
• Other windows, and reflections in what is on the screen.

2 What the file says

Phones and computers mark their screenshots, and name them with the date and time they were taken; some phones add the app that was open. hexscope calls it a screenshot either way, so you know to look.

Cropping is not always cutting. Until 2023, Pixel's Markup and Windows' Snipping Tool could write the cropped picture over the old file and leave the rest of the old one after it — the part you cropped, recoverable. hexscope shows bytes after the end of a picture, and the clean copy drops them.

3 Black it out properly

Blur and pixelation can sometimes be undone, and a highlighter that is not quite solid can be reversed by turning up the contrast. Use solid black. In hexscope, Black out part of the picture lets you drag boxes over what should go, and saves a new picture with the black in its pixels — and nothing of the original's hidden data at all.

The same goes for a screenshot pasted into a document: once it is in a PDF, a box drawn over it covers it and keeps it. hexscope finds a black box over a picture in a PDF, and its clean copy takes out what the box hid.