You can use a simple keyboard shortcut trick on your Mac to copy any screenshot directly to your clipboard. You can then paste it anywhere on your Apple computer, including third-party applications and iMessage.

If you have the Universal Clipboard feature enabled, you can even paste the screenshot on your iPhone or your iPad (taking AirDrop out of the equation).

Related: How to Screenshot on a Mac

When you're taking a screenshot, simply hold the Control key. For example, if you're taking a screenshot of a part of your Mac's screen, first use the Command+Shift+4 keyboard combination to enter the screenshot mode.

Capture Screenshot and Copy to Clipboard

Then, press and hold the Cntl key while you select the part of the screen that you want to capture.

Press Control Key on Mac Keyboard
Apple

The captured screenshot is now in your clipboard. You can share it with someone through any messaging or sharing application on your Mac, including Messages (as shown below).

Select a conversation and use the Cmd+V keyboard shortcut to paste the image in the text box. Hit the Enter key to send the screenshot.

Screenshot Pasted in Messages App

Alternatively, you can open the screenshot in Preview to edit it further. Open the Preview app, and from the "File" option in the menu bar, choose the "New From Clipboard" option. Alternatively, you can use the Cmd+N keyboard shortcut as well.

Click Create New From Clipboard

The screenshot will show up in a new Preview window where you can crop, annotate, or edit it in any manner that you like.

Screenshot Opened in Preview

Related: Use Your Mac's Preview App to Crop, Resize, Rotate, and Edit Images