As a documentarian, I’ve used ffmpeg command-line tool for a while now. It is a powerful tool that can do a lot of things. At work, I use it to convert videos and images.
Prerequisites
Install ffmpeg using homebrew.
Why use ffmpeg?
On macOS, Cleanshot X app by default captures the screenshot in png format. These files are large in file size and have a large resolution (not usually suitable for a web page).
How to use ffmpeg to convert png to jpg?
A jpg can have a smaller file size and is preferred for web pages. To convert a png to jpg using ffmpeg, use the following command:
ffmpeg -i input.png -preset ultrafast output.jpg