add troubleshooting doc

README.md

@@ -217,3 +217,67 @@ If you specify both a preferred architecture and a list of supported architectur
 
 If a preferred architecture is specified at the Pod level and is not compatible with the supported architectures listed in the command line, it will be ignored.
 
+## Troubleshooting guide
+
+
+### Image inspection
+
+This guide explain how to inspect container images to verify the supported architectures in case Noe's selection is not as expected.
+
+1. Authenticate with the registry (if required)
+
+```bash
+# in case of using docker
+docker login <registry-url>
+```
+
+2. Fetch the Image Manifest
+
+using a token/credential from the previous step, depending on the registry
+
+#### Docker Hub
+
+```bash
+curl -H "Authorization: Bearer <token>" \
+     -H "Accept: application/vnd.oci.image.index.v1+json,application/vnd.docker.distribution.manifest.list.v2+json" \
+     https://registry-1.docker.io/v2/<repository>/manifests/<tag>
+```
+
+#### Artifactory
+```bash
+export TOKEN=$(echo -n 'username:password' | base64)
+curl -H "Authorization: Basic $TOKEN" \
+     -H "Accept: application/vnd.oci.image.index.v1+json,application/vnd.docker.distribution.manifest.list.v2+json" \
+     https://<artifactory-url>/v2/<repository>/manifests/<tag>
+```
+
+3. Inspect the manifest
+
+in case of multi-archs
+
+```json
+{
+"manifests": [
+  {
+    "platform": {
+      "architecture": "amd64",
+      "os": "linux"
+    }
+  },
+  {
+    "platform": {
+      "architecture": "arm64",
+      "os": "linux"
+    }
+  }
+]
+}
+```
+
+In a single-architecture manifest:
+```json
+{
+  "architecture": "amd64",
+  "os": "linux"
+}
+```