How to edit, crop and blur a screenshot on a Mac

The built-in editor: Markup

Markup isn't an app you launch; it's a set of editing tools that appears in several places on the Mac. For screenshots, there are two ways in:

• From the floating thumbnail. Right after you take a screenshot with ⇧ ⌘ 4 or ⇧ ⌘ 3, a thumbnail sits in the bottom-right corner for a few seconds. Click it.
• From Preview. Open any image in Preview and click the Markup button — the pen tip in the toolbar.

(If the thumbnail never appears, it's turned off: ⇧ ⌘ 5 → Options → Show Floating Thumbnail. All the capture shortcuts are in how to screenshot on a Mac.)

What Markup can do

• Sketch and draw freehand. Sketch tidies up rough shapes, so a wobbly circle becomes a clean one.
• Shapes: lines, arrows, rectangles, ovals, a speech bubble and a few more. Set the outline color, fill color and line width in the toolbar.
• Text, with font, size and color.
• Loupe: a circular magnifier you drop over a detail and resize.
• Signature, captured from your trackpad, camera or iPhone.
• Crop and rotate.

Click Done and the changes are saved into the image. In Preview you also get Tools → Adjust Size to make a Retina screenshot smaller before sending it, and Adjust Color for exposure and contrast.

Where Markup falls short

• No blur or pixelate. This is the big one. There's no way to blur an email address, a face or an account number.
• No numbered steps. To label a sequence you type 1, 2, 3 in separate text boxes and line them up by hand.
• No callouts with a separate magnified panel, no stickers.
• No way to remove something from the image — a stray notification, a cursor, a watermark — other than covering it.
• The edit is one shot. Once you click Done in the thumbnail, the annotations are flattened into the picture; you can't go back and move an arrow.
• Annotations can't go past the edge. An arrow pointing in from outside the image gets clipped.

How to crop a screenshot on a Mac

Cropping is the edit people make most, and the Mac gives you three ways to do it.

From the floating thumbnail

1. Take the screenshot and click the thumbnail in the bottom-right corner.
2. Click the Crop button in the Markup toolbar.
3. Drag the corners and edges of the frame to the area you want to keep.
4. Click Done. The cropped image replaces the original file.

In Preview

1. Open the screenshot in Preview.
2. Drag a rectangle over the part you want to keep. The size in pixels appears as you drag.
3. Press ⌘ K (Tools → Crop), then ⌘ S to save.

Preview saves the crop into the same file. You can get the original back with File → Revert To, but if you'll need both, File → Duplicate before cropping is simpler.

Skip the crop: capture just the area

Often the quickest crop is not needing one. ⇧ ⌘ 4 lets you drag over exactly the area you want, and ⇧ ⌘ 4 then Space captures a single window without the rest of the screen. To make a Retina screenshot smaller rather than tighter, use Tools → Adjust Size in Preview.

How to hide private info without a blur tool

Since Markup can't blur, the reliable method is a solid box:

1. In Markup, open Shapes and pick the rectangle.
2. Draw it over the text you want to hide.
3. Set the fill color to black (or white, to match the background) so it's fully opaque.
4. Click Done.

A black box is ugly but secure. When the screenshot is going into documentation or a slide, a pixelated or blurred area looks far cleaner and still makes clear that something was hidden. If you do pixelate, use big blocks: a light blur on a short string like a PIN can sometimes be reversed.

ShotDock's screenshot editor

ShotDock opens every capture straight into an editor — no thumbnail to catch in time. It has more than twenty tools and each one is a single letter, like in Photoshop or Figma, so you rarely touch the toolbar.

Annotate

• A arrow, L line, R rectangle, O oval, Q hand-drawn circle, P pencil, H highlighter.
• T text callouts with a tail you can aim, or plain text with a shadow; N handwritten-style text.
• S numbered steps: click, click, click and you get 1, 2, 3 — the counter keeps track for you.
• Z magnifier: mark a detail and it's blown up (1.5× to 6×) in a panel joined by a line, without cropping the shot.
• F stickers and emoji, searchable.

Hide

• M pixelate and B blur. Drag over a name, an email or a card number. Both stay as objects, so you can move or resize them later.

Retouch

This is where ShotDock goes beyond a typical screenshot editor, with tools usually found in photo editors:

• E content-aware erase: paint over a notification, a logo or an object and it rebuilds the background behind it, matching texture and gradient instead of leaving a blotch.
• J dust removal: sweep over a scanned document and it fills in the specks one by one, while leaving letters, accents and punctuation alone.
• K clone, W warp, D dodge and burn, G pinch and bloat.
• C crop and V select to move anything you've drawn.

Things that just work

• Undo everything. ⌘ Z and ⇧ ⌘ Z work on every stroke, including the retouching tools.
• The canvas grows. If an arrow or callout runs off the edge, the image widens instead of clipping it.
• Tools remember their settings — color, width, size — even after you quit.
• Finish with one key. ⎋ Esc copies and closes, ↩ saves, ⌘ ↩ uploads and copies a link (to ShotDock's cloud or your own S3 bucket).

The same editor opens after a scrolling capture, so long screenshots get every tool too. ShotDock needs macOS 14 or later on an Apple Silicon Mac; the trial has every tool and no account.

Frequently asked questions