How to Annotate and Crop Screenshots on Mac Without Preview

Annotate and crop Mac screenshots using the floating thumbnail, Quick Look Markup, and Finder Quick Actions, without opening Preview or any other app.

1. Catch the floating thumbnail. After any capture, a thumbnail appears in the bottom right corner and lingers briefly. Click it before it goes and the image opens straight into Markup. Ignore it and the file saves to whatever location the screenshot toolbar is set to.
2. Work the Instant Markup toolbar. The toolbar across the top holds Sketch, Draw, Shapes, Text, Sign, Shape Style, Border Color, Fill Color, and Text Style. Shapes includes a loupe that magnifies part of the image and a highlight box that dims everything outside it. Click Done to save.
3. Crop from the same toolbar. Use the crop control at the right of the Markup toolbar. Drag the corner handles to set the frame you want, then confirm to apply it. Command + Z steps the crop back if the frame was wrong, as long as you have not clicked Done.
4. Mark up straight from Quick Look. Select any image in Finder and press the Space bar. The Quick Look window opens. Click the Markup button, the pencil-tip icon near the top right of that window, and the same toolbar appears. Your changes save back into the file when you click Done.
5. Reach Markup from Finder Quick Actions. Control-click an image in Finder and open the Quick Actions submenu. Choose Markup. The editor opens in place, over the Finder window, with no application launch. The same command appears in the Finder preview pane under More when that pane is showing.