What Is GitHub Camo and Why Does It Exist?
Whenever you embed an external image into a GitHub README, GitHub does not load that asset directly from the remote server. Instead, GitHub routes the request through its proprietary proxy: camo.githubusercontent.com.
Camo was introduced to address two critical security vectors: enforcing strict SSL/TLS across all assets, and preventing third-party servers from tracking developers' IP addresses and geolocation when viewing repositories.
How to Force Evict GitHub Camo Cache
# Technique 1: Send an HTTP PURGE Request to GitHub Camo
curl -X PURGE "https://camo.githubusercontent.com/0123456789abcdef..."
# Technique 2: Append a Timestamp Query Parameter in Markdown
# Camo Header Requirements Matrix
| Remote Server Header | Camo Behavior | Recommended Value for Dynamic Widgets |
|---|---|---|
| Cache-Control | Camo mirrors remote TTL | no-cache, no-store, must-revalidate, max-age=0 |
| Content-Type | Strictly enforced | image/svg+xml or image/png |
| Content-Security-Policy | Strips script tags | default-src 'none'; style-src 'unsafe-inline' |
| Access-Control-Allow-Origin | Ignored by Camo | * |
Frequently Asked Questions
❓ Why does my dynamic SVG show a broken image icon?
GitHub Camo enforces strict XML sanitization. If your SVG contains embedded script tags or foreignObject elements, Camo refuses to proxy the file and returns a broken image.
❓ What is the maximum file size Camo will proxy?
GitHub Camo enforces an image threshold of approximately 5MB. Assets exceeding this limit fail to load.