How do I get rid of the shading of screen after taking screenshot?
You can potentially solve this by entering the following commands in Terminal followed by the Enter or Return key:
defaults write com.apple.screencapture disable-shadow true killall SystemUIServer
The above commands should solve the issue.
If you want to change back, you can use the following terminal commands:
defaults write com.apple.screencapture disable-shadow false
If the above doesn’t work, you can use any third party image editing app, open the screenshot with the editor and crop off the drop shadow.