How to Capture Firefox Screenshots for Web Testing

Different Methods to Capture Firefox Screenshot

Here are different methods to capture screenshots in Firefox using the built-in tool, developer tools, testing tools/frameworks, headless mode for CI/CD, and using cloud-based testing platforms such as TestMu AI.

Method 1: Use Firefox Built-in Screenshot Tool

If you’re testing manually, the simplest way to capture a Firefox screenshot is with its native tool. You don’t need an extension for this.

Here’s how you do it:

• Open the web page you want to capture.
• Right-click anywhere on the web page and select Take Screenshot.

If you don’t see the option? Open about:config in a new tab, search for extensions.screenshots.disabled, and make sure it’s set to false.

You can also use these Firefox screenshot shortcuts:

• Windows/Linux: Ctrl + Shift + S
• macOS: Cmd + Shift + S

• Once the tool is active, choose one of the following:
  • Drag to select a region, or click a single element to capture it
  • Save visible, for the part of the page currently on screen
  • Save full page, for the whole scrollable page

  

• Save the file locally or copy it to your clipboard.

Note: Capture automated Firefox screenshots across 3,000+ browser and OS combinations. Try TestMu AI Today!

Method 2: Capture Screenshots With Firefox Developer Tools

Sometimes you want more control than the built-in tool gives you. That’s where Developer Tools come in.

Here’s what you do:

• Open Developer Tools using the Firefox screenshot shortcut.
  • F12 or Ctrl + Shift + I (Windows/Linux)
  • Cmd + Option + I (macOS)
• In the Developer Tools panel, click the three-dot menu (top-right corner of the DevTools bar) and select Settings from the dropdown.

• In the Settings page, scroll to Available Toolbox Buttons and check the option Take a screenshot of the entire page.

• After enabling, you’ll see a camera icon appear in the DevTools toolbar and click the camera icon to capture a screenshot of the entire page.

Pro-tip: If you’re debugging CSS or verifying layout alignment, you can use Screenshot Node to grab just one component. This keeps your screenshots focused and avoids extra noise.

Method 3: Automate Screenshots With Selenium and FirefoxDriver

Manual screenshots are fine when you’re exploring. But once you’re running regression tests, you need automation.

With automation testing tools like Selenium, you can tell Firefox to take screenshots at any step. Check out this blog to get started with capturing screenshots in Selenium.

Here’s an example:

from selenium import webdriver

driver = webdriver.Firefox()
driver.get("https://example.com")

# Capture screenshot
driver.save_screenshot("homepage.png")

driver.quit()

How this helps you:

• You can capture screenshots after key actions in your test flow (like after logging in or submitting a form).
• You can save a screenshot whenever a test fails, so debugging is easier.
• You can create baseline images for visual regression testing.

Method 4: Capture Firefox Screenshots in Headless Mode

When your tests run on a server or inside a pipeline, there’s usually no GUI. Firefox can run in headless mode and still capture screenshots.

Here’s how you set it up:

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
options.add_argument("-headless")  # Run Firefox without UI
driver = webdriver.Firefox(options=options)

driver.get("https://example.com")
driver.save_screenshot("ci_result.png")

driver.quit()

You can attach screenshots to your CI test reports. If a test fails on the server, you can download the screenshot and see exactly what Firefox rendered at that moment.

Method 5: Capture Firefox Screenshot With TestMu AI

If you need more than basic screenshots, cloud-based testing platforms like TestMu AI give you a powerful way to scale. Instead of taking screenshots only on your local machine, you can instantly capture on an online browser farm of multiple Firefox versions and different operating systems, such as Windows and macOS.

Features:

• Cross Browser Testing: Ensure your website looks and works consistently across different browsers, versions, real devices, and operating systems.
• Automated Screenshot Testing: Capture full-page screenshots in Firefox at once across various environments without manual effort.
• Automation Testing: Run automated tests on the cloud using tools like Selenium, Cypress, Playwright, Appium, and more.
• Screenshot Comparison Tool: Compare new screenshots with baselines to detect unintended UI changes.
• Responsive Testing: Check with LT Browser how your web app adapts to different screen sizes and resolutions.

To capture screenshots of a desktop website in real-time with TestMu AI, here are the steps:

• Go to Real Time > Browser Testing.
• Enter your website URL, pick the OS (Windows or macOS), then select Firefox along with the version and screen resolution you want. Finally, hit Start.

• Once the Firefox session loads on your chosen OS and resolution, you’ll see the website running in real time. From here, you can interact with the page exactly as you would on a local machine.

After launching the browser session, simply hit the Screenshot icon from the left panel to capture and store the Firefox view on your local machine.

For more information, you can check out this guide on desktop browser testing with TestMu AI.