Fix screenshot links

Author: colinmcneil

src/extension/Dockerfile

@@ -26,7 +26,7 @@ LABEL org.opencontainers.image.title="AI Tool Catalog" \
     org.opencontainers.image.description="AI Tool Catalog" \
     org.opencontainers.image.vendor="Docker Inc" \
     com.docker.desktop.extension.api.version="0.3.4" \
-    com.docker.extension.screenshots='[{"alt":"screenshot of the extension UI", "url":"https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/main/src/extension/ui/src/assets/screenshot1.png"}, {"alt":"Screenshot of MCP Client configuration", "url":"https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/main/src/extension/ui/src/assets/screenshot2.png"}]' \
+    com.docker.extension.screenshots='[{"alt":"screenshot of the extension UI", "url":"https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/refs/heads/main/src/extension/ui/src/assets/screenshots/screenshot1.png"}, {"alt":"Screenshot of Tile configuration", "url":"https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/refs/heads/main/src/extension/ui/src/assets/screenshots/screenshot2.png"}, {"alt":"Screenshot of MCP Client configuration", "url":"https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/refs/heads/main/src/extension/ui/src/assets/screenshots/screenshot3.png"}]' \
     com.docker.desktop.extension.icon="https://raw.githubusercontent.com/docker/labs-ai-tools-for-devs/main/src/extension/ui/src/assets/extension-icon.png" \
     com.docker.extension.detailed-description="A catalog of Dockerized MCP tools for developers" \
     com.docker.extension.publisher-url="https://www.docker.com/" \