Maybe another right click option like 'Save screenshot to Raindrop.io' with options to save the full page, the visible area or the one I would use the most - save selection where you can select the area on the page you'd like to save.

The new built-in Firefox 'Take a screenshot' has great functionality for reference.

This feature would be really helpful for bookmarking favourite UI component designs and I imagine would be a big draw for designers out there