“Explain and Send Screenshots” is a browser extension (new to me) that gives you the ability to capture screenshots and to record video of your screen. Once the capture is performed, you can write text, crop an image and perform other functions in the editor that is built in (such as insert arrows, lines, and circles to point things out). I especially like the option of uploading my own images into the editor; which, is an option you do not typically see in these type of browser extensions.
I am still playing around with this extension; however, I can tell you the developer is top notch, for which I encourage you to explore some of his other browser extensions (that in my opinion are the best out there).
Source: Explain and Send Screenshots – Jason Savard