Taking a Screenshot; Windows > Start > search box > Snip. Select Snipping Tool. Use a compressed image type like PNG or JPG to save the screenshot. Save the picture(s) to your desktop. Press the Reply button. Then press the Add images; Browse button.

I know of an add-on to screenshot the video player (not the entire page) on YouTube: https://addons.mozilla.org/firefox/addon/youtube-screenshot-button/

I don't know if there is a similar tool for other sites.

when i fullscreen with adobe flash on, i see screen tearing too.

To do a proper screenshot you need Snipping Tool which I think is part of Windows 10 and don't recall it on Windows 7 or you need to purchase software like Snagit to do screenshots. So what are you doing a screenshot with that is doing the tearing?

i printscreen myself to post on twitter so i don't have to take selfies every time. if i use chrome, i just double click my stream to fullscreen and printscreen to save my screenshot. but on firefox, after i double click my steam, the stream looks like vsync is off and screenshots i took are not fullscreen (includes chat and everything on the website just like while i'm not in fullscreen mode).

maybe press the PrintScreen button on the keyboard and then paste the result into Paint? (mspaint.exe)

that's what i did after i pressed f11. it pasted the whole website not just the fullscreen screenshot. and when i turned fullscreen, the screen is tearing, no anti-aliasing at all.

PrintScreen key is not something to use for screenshot if you ever pasted PrintScreen onto a Word Document it's full screen in a small format and pretty limited what you can do and not something that can view unlike Snagit which does a proper screenshot.

The developer tools have a button to take a screenshot of a specific node, but this requires that you are familiar with these tools.

• https://developer.mozilla.org/en-US/Tools/Page_Inspector
• https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_HTML#Screenshot%20Node

See Taking a screenshot of an element:

• https://developer.mozilla.org/en-US/docs/Tools/Taking_screenshots

It may not be that difficult to use the developer tools to take a screenshot.

You can use a command in the Browser Console to take a screenshot of a specific node (CSS selector). You can get the selector via the Inspector window in the left pane via the right-click context menu (Copy -> CSS selector), see the links posted above. You can use the button on the Inspector's toolbar to select an element by clicking it. You may need to go back (higher) in the DOM tree to get a suitable element.

Paste or type this code in the command line of the Web Console and paste the CSS selector of the player windows after the --selector switch (leave a space and surround with quotation marks (")).

:screenshot --selector "<CSS-selector>"

You will hear a click and the console will display a message that the screenshot is saved .

Once you know the selector and have constructed a working command then you can recall this command via the cursor Up key on the command line and save a copy.

You can use this command in the Web Console for more info about available parameters.

:screenshot --help

An example from the question page:

:screenshot --selector "#question-1247282"

is it possible to just make it work with printscreen button and paste it to paint?

You need to have the Web Console command line visible and accessible to be able to invoke the command, so that it isn't possible to use the print screen button. You can dock the console at the bottom or as a separate window and make the window as small as possible.