Move flag image sizing from HTML to CSS

Removed explicit width attributes from flag <img> tags in gallery.md and added a CSS rule to set image width to 96px. This centralizes image sizing in CSS for easier maintenance and cleaner markup.

Author: HatScripts

gallery.css

@@ -7,6 +7,10 @@
   padding: 1em;
   width: 160px;
 }
+.container > div img {
+  width: 96px;
+  height: auto;
+}
 code {
   white-space: nowrap;
 }