I use shift + control + command + 4 a lot. The default fileformat in my case is .tiff. I have tried to change it to .png using these setting: https://www.laptopmag.com/articles/change-default-screenshot-file-format-macos
And I have tried to restart, but it does not seem to save the file in png in the clipboard which is what I'm interrested in. I have a Macbook Pro 15¨ (with touchbar) from 2016. I'm running macOS 10.13.3.
Kind regards, JJ