Try light/dark mode image

REPORT.md

@@ -66,7 +66,13 @@ p4runtime (python library for interacting with switches).
 
 Furthermore, we reused the load_balance exercise from the [p4lang/tutorials](https://github.com/p4lang/tutorials) repository. This is a simple load balancer, which hashes connections based on the source IP, source port, destination IP, destination port, and protocol into 2 buckets, which represent hosts. The output of this hash is 0 or 1, which is then used to index the target host (`h2` or `h3`) using the `ecmp_nhop` table.
 
-<img src="assets/simple_lb_light.png" alt="initial_lb" width="500"/>
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="assets/simple_lb_light.png">
+  <source media="(prefers-color-scheme: light)" srcset="assets/simple_lb_dark.png">
+  <img alt="Shows a graph of nodes and switches to demostrate a simple load balancing solution." src="assets/simple_lb_light.png">
+</picture>
+
+<img src="" alt="initial_lb" width="500"/>
 
 ### Controller
 Relevant PRs: