fix(blog): fixture image codec — 1600px JPEG, 145K

content/blog/hello-world-again.md

@@ -11,7 +11,7 @@ Skeleton post. Each element below exercises one rendering path of the blog engin
 2. Build-time code highlighting — Hydra snippet below.
 3. GFM table — bottom of this post.
 
-![A Hydra sketch rendering a glowing nebula, shown in the Hydra editor](/images/blog/hello-world-again/edge.png)
+![A Hydra sketch rendering a glowing nebula, shown in the Hydra editor](/images/blog/hello-world-again/edge.jpg)
 
 ```js
 osc(20, 0.01, 1.4)