How to Crop a Screenshot on Mac

Mac screenshots are fast to capture, but they rarely match the exact crop you need for a README, pull request, or support ticket. This guide covers the built-in macOS capture shortcuts and how to crop the result locally in your browser.

Step 1: Capture the screenshot on macOS

Common shortcuts:

• Full screen: Shift + Command + 3
• Selected window: Shift + Command + 4, then press Space, click the window
• Selected region: Shift + Command + 4, drag to select an area

Screenshots save to your Desktop by default (or the location set in Screenshot settings).

Step 2: Open a local cropper

Upload the PNG file, drag it into the tool, or copy the image and paste it if your browser supports clipboard image access.

DevCove Image Cropper processes everything in the browser. Your screenshot is not uploaded to a server.

Step 3: Choose aspect ratio and output size

For documentation hero images, 16:9 is a common choice. For avatars or app icons during early prep, try 1:1.

Pick an output preset:

• Crop size keeps the exact pixel dimensions of your selection
• 512 × 512 or 1024 × 1024 when you need a square export
• Custom when a doc template requires exact width and height

Step 4: Download PNG or JPEG

PNG preserves sharp UI text. JPEG produces smaller files when you do not need transparency.

If WebP export is disabled in your browser, use PNG or JPEG—Safari and some iOS browsers may not encode WebP from Canvas.

Tips for developer workflows

• Crop once in the tool instead of re-exporting from design apps for simple doc updates.
• Pair cropped screenshots with Markdown Preview when writing README files.
• Remember that browser cropping removes EXIF metadata; that is expected for web-ready assets.

What this does not replace

This workflow does not silently capture your screen inside the browser. You still use macOS shortcuts first, then crop locally— which keeps permissions clear and avoids privacy surprises.