Double the size of the Firefox image.

source/3/3.1/3.1.1/firefox.rst

@@ -20,7 +20,7 @@ Firefox has features of other web browsers and its own ones, such as:
 Usage/Screenshots
 ----------------------
 .. image:: firefox-screenshot.png
-   :width: 40%
+   :width: 80%
 
 Version
 ----------
@@ -29,4 +29,4 @@ Lubuntu currently ships with the latest version of Firefox, Firefox Quantum.
 How to launch
 ----------------
 To open Firefox, click on the Firefox icon (red/orange fox covering a blue sphere) in the Lubuntu Menu.
-You can also type and run `firefox` in the terminal to open the browser.
+You can also type and run `firefox` in the terminal to open the browser.