Python isn't a Firefox software so you need to contact their support for Python and how to do what your asking here.

You could do that via -headless mode.

• https://wiki.mozilla.org/firefox/CommandLineOptions

• /questions/1256647 Headless Firefox doesn't work
• https://searchfox.org/mozilla-release/source/browser/components/shell/HeadlessShell.jsm

See also:

• https://www.google.com/search?sa=N&num=100&q=firefox%20headless%20screenshot

• https://github.com/puppeteer/puppeteer/tree/main/examples
• https://github.com/puppeteer/puppeteer/blob/main/examples/screenshot-fullpage.js

You can activate the "Take screenshot of the entire page" feature in the Firefox and Chrome web developer tools using Python and Selenium. Here's an example code snippet that demonstrates how to do this:

from selenium import webdriver

# Set up the web driver for Firefox or Chrome
# Replace "firefox" with "chrome" to use the Chrome driver
driver = webdriver.Firefox()

# Navigate to the web page you want to capture
driver.get("https://www.example.com")

# Use the execute_script method to activate the developer tools and take a screenshot of the entire page
driver.execute_script("window.scrollTo(0, 0);")
developer_tool_command = 'window.setTimeout(function(){devtools.inspectedWindow.eval("screenshot.save();");}, 2000);'
driver.execute_script(developer_tool_command)

# Wait for the screenshot to be taken and saved
driver.implicitly_wait(10)

# Close the browser window
driver.quit()

In the above code, the execute_script method is used to activate the developer tools and execute the screenshot.save() command. The window.scrollTo(0, 0) method call is used to ensure that the entire web page is captured, even if it's longer than the current viewport.

Note that the execute_script method may not work in headless mode. If you're running the script in headless mode, you may need to use a different method to activate the developer tools and take the screenshot.