Some terminals are using custom escape sequences to display base64 encoded images (`ESC ] 1337`) or from a path (`ESC ] 1338`)

For example, iTerm uses the first one and provides a simple shell command to test it: https://iterm2.com/documentation-images.html

Some testing software, in my case Rails System tests, can display the screenshot of failed test directly in the terminal, see https://github.com/rails/rails/blob/main/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb#L116 for their implementation

This is very useful when working on those tests.