diff --git a/README.md b/README.md
index 2178b2f..9cb9922 100644
--- a/README.md
+++ b/README.md
@@ -125,7 +125,7 @@ side of the mapping in the compose file — the right side is the internal port,
 the one the process listens on.
 
 
-Official multi-architecture Docker images (`linux/amd64` and `linux/arm64`) are published automatically to the GitHub Container Registry (GHCR):
+Official multi-architecture Docker images (`linux/amd64` and `linux/arm64`) are published automatically to the GitHub Container Registry (GHCR) on pushes to `master` with changes in `src/`. An automated retention policy maintains strictly the last 3 versions:
 
 ```bash
 docker pull ghcr.io/pathbit/9rtksync:latest
@@ -337,6 +337,18 @@ make test
 PYTHONPATH=src python3 -m unittest discover -s tests -p "test_*.py"
 ```
 
+### Option 3. Automated Docker Image Validation with Testcontainers
+
+Validates that the generated Docker image boots cleanly, exposes the web dashboard on port 9090, responds on `/login` (200 OK) and `/healthz`, and executes CLI commands:
+
+```bash
+# Install package with test dependencies
+pip install ".[test]"
+
+# Run Testcontainers validation suite
+python3 -m unittest tests/test_container.py -v
+```
+
 ---
 
 ## Contributing and Branch Protection