How to crop and annotate a screenshot

Every laptop already has an annotation tool. None of them advertise it, and all three are good enough that installing something is usually unnecessary.

Updated 15 September 2026

Windows: Snipping Tool#

Click the notification after a capture and it opens in the editor. For an image you already have, open Snipping Tool and paste with Ctrl+V.

Crop: the crop icon, then drag the handles. Enter commits.

Draw: ballpoint pen and highlighter, both with adjustable colour and thickness. Click a selected tool a second time to open its options.

The ruler is the tool people miss. Click the ruler icon and a translucent straightedge appears on the canvas — drag it into position, then draw along its edge for perfectly straight lines. Scroll with the pointer over it to rotate it. There's a protractor for arcs behind the same button.

Shapes, on recent versions: rectangles and ovals with fill or outline. The quickest way to circle something.

Redact: on Windows 11, the text actions button finds email addresses and phone numbers in the image and blanks them in one click. For anything else, draw a filled black rectangle over it.

Ctrl+Z undoes, Ctrl+S saves, Ctrl+C copies the annotated version.

Mac: Markup#

Click the floating thumbnail immediately after a capture and Markup opens. For a saved file, open it in Preview and press Cmd+Shift+A for the Markup toolbar.

Markup is the most capable of the three built-in editors:

• Shapes including arrows, with adjustable curve and thickness.
• Shape recognition. Draw a rough circle with the sketch tool and it snaps to a clean one. Rectangles, arrows and stars too. Draw badly on purpose and it works.
• Text with real font control.
• Signature, stored and reusable.
• Loupe — a magnifier you place on the image, resizable and zoomable, for calling out fine detail without cropping.
• Instant Alpha, in Preview's toolbar, removes a background colour by clicking it.

Crop by dragging a selection with the rectangle tool, then Cmd+K.

To redact, use a filled rectangle rather than the highlighter — the highlighter is translucent and the text stays readable underneath. This mistake has leaked real data.

Chromebook: Gallery#

Screenshots open in Gallery from the notification, or from Files.

Crop and rotate, resize to specific dimensions, adjust brightness, and annotate with a pen or highlighter. It opens straight from the notification after a region capture. On stylus models the pen pressure is recognised.

Gallery works offline, which matters on a Chromebook. It saves back over the original by default, so use Save a copy if you want to keep the untouched capture.

Annotating well#

The tools are easy; useful annotation is a skill. Four things that make a screenshot clearer:

• One idea per capture. Three arrows pointing at three things means the reader has to work out which matters. Take three captures.
• Crop hard. Everything irrelevant in frame competes with the thing you're pointing at. Crop to the dialog, not the desktop.
• Use one colour. A single strong colour reads as annotation. Four colours read as decoration.
• Point from outside. An arrow starting in empty space and ending at the target is clearer than a box drawn around it, especially if the interface already has boxes.

Redacting properly#

Also check the rest of the frame. Browser tabs, notification banners, file paths containing your name, and a visible calendar all leak more than people expect — a particular risk when capturing a meeting, where other people's names are on screen too. Crop before you redact.