How to get lower resolution image in current clipboard after using macOS screen-capture shortcut?

I have set Command + Shift + 4 to a keyboard shortcut to take a screenshot and save to clipboard, usually, I will paste this image for next usage.

But I want to lower the resolution of the image in the current clipboard because it's too big, how to do this?

• With the image at Clipboard, you can open Preview.app, hit command+N.

• Go to Tools menu > Adjust Size..., make modifications.

• Using the selection, cover the whole image, liberally. Don't worry if you've got lot of padding around it.

  

• Hit command+C and paste wherever you want.

"Export as..." also provides some options to downsize the image.