https://support.mozilla.org/en-US/questions/767346
for Mac screenshots, try the answer on this page. Mozilla Firefox support link, so if not suitable for you, you can browse.
(If you open the read answer in context, there's a snipping tool for Microsoft there too, for screenshots)
-------------------------------------------------------------------------------------------------------------------------------
Buttercup: You mock my pain! Man in Black: Life is pain, Highness. Anyone who says differently is selling something.
