How To Use Firefox to take Mobile-first Screenshots *Fast* on Any OS

[nelsonic]

If you don't already have Firefox installed, download and install it: #9 "Install a Dev Browser"! Do it now! ⏳

Once you have Firefox installed, open the Application.

In the top-right corner of the Firefox window, click on the "3 Horizontal Lines" (pancakes) Menu, Then Click on "More tools":

In the "More Tools" sub-menu, click on "Customise Toolbar":

Drag the "Screenshot" icon to your toolbar:

You should end up with the following:

Once you have everything setup, it's easy to take full-screen screenshots by clicking on the "Screenshot" (scisors) icon
followed by "Save full page":

Once you've taken the screenshot, you can click "Copy":

And paste the screenshot into any GitHub Issue Comment:

This excludes all the browser chrome including the URL.

[nelsonic]

An Even Faster Way!

Open Firefox Developer Tools, click on the "Responsive Design Mode" (cmd+alt + M)
Then click on the little Camera Icon to instantly take a Screenshot of the viewport:

That will automatically take and download the screenshot to your /downloads directory,
e.g:

You can then drag that screenshot into your Paint program #53 to highlight anything
and then upload it to GitHub (or wherever) to share it.

The reason I go through the longer process above is to take full-page screenshots.
e.g. of an entire landing page of a website in one go!