doc: Update README.md

README.md

@@ -1,10 +1,12 @@
 # DiffHighlighter
 
-A diff file highlighter extension for Thunderbird.
+A diff file highlighter extension for Thunderbird, especially useful when you are reviewing a patch.
+
+![image](https://github.com/user-attachments/assets/e3b19a93-cdee-4203-86e2-7260b6ce33c9)
 
 ## How to use?
 
-You can download the `colorediffs.xpi` file directly from the release, you can also build it yourself on a Linux machine:
+You can download the `colorediffs.xpi` file directly from the [latest release](https://github.com/tristone13th/DiffHighlighter/releases), you can also build it yourself on a Linux machine:
 
 1. Ensure you have `zip` installed;
 2. cd to this project's source folder, execute `make xpi`;