Fix blog route matching article header

src/blog/tanstack-router-route-matching-tree-rewrite.md

@@ -6,10 +6,12 @@ authors:
   - Florian Pellet
 ---
 
-![Big performance number](/blog-assets/tanstack-router-route-matching-tree-rewrite/header.png)
+![Fantasy landscape illustration used as the article header](/blog-assets/tanstack-router-route-matching-tree-rewrite/header.jpg)
 
 We achieved a 20,000× performance improvement in route matching in TanStack Router. Let's be honest, this is _definitely_ cherry-picked, but the number is real and comes from a real production application. More importantly, it shows that matching a pathname to a route is no longer bottlenecked by the number of routes in your application.
 
+![Big performance number](/blog-assets/tanstack-router-route-matching-tree-rewrite/big-number.png)
+
 ## The Real Problem: correctness, not speed
 
 One big responsibility of a router is to match a given URL pathname (e.g., `/users/123`) to a route definition (e.g., `/users/$userId`). This is deceptively complex when you consider all the different types of route segments (static, dynamic, optional, wildcard) and the priority rules that govern which route should match first.