fixed missing .png

Author: worldsolutions

index.html

@@ -9,7 +9,7 @@ <h1>GitHub Pages</h1>
     <h2>Welcome to my GitHub Pages site!</h2>
     <h3>Happy Fourth of July</h3>
     <img
-      src="fireworks"
+      src="fireworks.png"
       alt="Fourth of July fireworks"
       width="600"
       height="400"