Use your clipboard to copy and paste images.
To Catch Screen on your Mac use ⇧ + ctrl + cmd ⌘ + 4
screen to catch current window into clipboard,
☛ you can paste picture image to start drawing (ctrl + v)
You can use print
screen button on your keyboard to catch current screen to clipboard,
next you can paste image below to get shareable link (ctrl + v)
You can use your camera to take photo