diff --git a/docs/ci-plugin-image-sync.md b/docs/ci-plugin-image-sync.md
new file mode 100644
index 00000000000..432e1c4482f
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@@ -0,0 +1,173 @@
+# CI Plugin Image Substitution Guide
+
+## Problem
+
+OADP plugin images are built in OpenShift CI and promoted to an
+ImageStream, but the quay.io mirrors that `pkg/common/common.go`
+references can lag behind by hours. Without explicit substitution
+entries, CI e2e tests run against stale images and may miss
+regressions introduced by the code under test.
+
+## Solution
+
+The ci-operator configs in
+[openshift/release](https://github.com/openshift/release) support two
+mechanisms that, together, inject freshly promoted CI images into the
+operator at test time:
+
+| Mechanism | Purpose |
+|-----------|---------|
+| `base_images` | Import a plugin image from its CI ImageStream into the test namespace |
+| `operator.substitutions` | Replace the quay.io pullspec in `config/manager/manager.yaml` with the imported CI image |
+
+The operator binary reads each plugin image from the `RELATED_IMAGE_*`
+environment variables defined in `config/manager/manager.yaml`. The
+`operator.substitutions` entry overwrites the value of the
+corresponding env var so that the running operator deploys the CI build
+instead of the quay.io mirror.
+
+## Step-by-step checklist for adding a new plugin image
+
+### 1. Add the image constant
+
+In `pkg/common/common.go`, add a new constant to the `// Images` block:
+
+```go
+NewPluginImage = "quay.io/konveyor/new-plugin:oadp-1.6"
+```
+
+### 2. Add the RELATED\_IMAGE env var
+
+In `config/manager/manager.yaml`, add a new environment variable to the
+manager container:
+
+```yaml
+- name: RELATED_IMAGE_NEW_PLUGIN
+  value: quay.io/konveyor/new-plugin:oadp-1.6
+```
+
+### 3. Find the plugin repo's CI tag
+
+Look up the plugin repo's ci-operator config in openshift/release. For
+example, for `openshift-velero-plugin`:
+
+```
+ci-operator/config/openshift/openshift-velero-plugin/
+```
+
+In that config, find the `promotion.to` stanza to identify the
+**namespace** and **name** of the target ImageStream, and find the
+`images[].to` field to get the **exact tag** the image is promoted as.
+
+Example (from the openshift-velero-plugin config):
+
+```yaml
+promotion:
+  to:
+  - namespace: konveyor
+    name: oadp-1.6
+images:
+- to: openshift-velero-plugin
+```
+
+The important values are:
+- **namespace**: `konveyor`
+- **ImageStream name**: `oadp-1.6`
+- **tag**: `openshift-velero-plugin`
+
+### 4. Add a `base_images` entry
+
+In each OADP variant config file under
+`ci-operator/config/openshift/oadp-operator/`, add a `base_images`
+entry that imports the plugin image:
+
+```yaml
+base_images:
+  # ... existing entries ...
+  openshift-velero-plugin:          # key must match the tag from step 3
+    namespace: konveyor
+    name: oadp-1.6
+    tag: openshift-velero-plugin    # must exactly match the "to:" tag
+```
+
+> **Important**: the `tag` value here MUST exactly match the `to:` field
+> from the plugin repo's ci-operator config. A mismatch causes the
+> import to silently fail, and CI tests fall back to the stale quay.io
+> image.
+
+### 5. Add an `operator.substitutions` entry
+
+In the same variant config files, add a substitution that replaces the
+quay.io pullspec with the CI image:
+
+```yaml
+operator:
+  substitutions:
+  # ... existing entries ...
+  - pullspec: quay.io/konveyor/openshift-velero-plugin:oadp-1.6
+    with: pipeline:openshift-velero-plugin
+```
+
+The `pullspec` must match the value used in
+`config/manager/manager.yaml` (and `pkg/common/common.go`) exactly.
+The `with` field references the base image imported in step 4 via the
+`pipeline:` prefix.
+
+### 6. Update ALL variant configs
+
+Repeat steps 4 and 5 in **every** variant config file for the branch.
+These files follow the naming pattern:
+
+```
+ci-operator/config/openshift/oadp-operator/openshift-oadp-operator-oadp-1.6__4.XX.yaml
+```
+
+For example:
+- `openshift-oadp-operator-oadp-1.6__4.22.yaml`
+- `openshift-oadp-operator-oadp-1.6__4.23.yaml`
+- `openshift-oadp-operator-oadp-1.6__4.24.yaml`
+- etc.
+
+Missing a variant means that OCP version's CI jobs will still use the
+stale quay.io image.
+
+## Complete example: openshift-velero-plugin
+
+Below is a condensed example showing all the pieces for the
+`openshift-velero-plugin` image.
+
+**`pkg/common/common.go`** (already present):
+
+```go
+OpenshiftPluginImage = "quay.io/konveyor/openshift-velero-plugin:oadp-1.6"
+```
+
+**`config/manager/manager.yaml`** (already present):
+
+```yaml
+- name: RELATED_IMAGE_OPENSHIFT_VELERO_PLUGIN
+  value: quay.io/konveyor/openshift-velero-plugin:oadp-1.6
+```
+
+**ci-operator variant config** (in openshift/release):
+
+```yaml
+base_images:
+  openshift-velero-plugin:
+    namespace: konveyor
+    name: oadp-1.6
+    tag: openshift-velero-plugin
+
+operator:
+  substitutions:
+  - pullspec: quay.io/konveyor/openshift-velero-plugin:oadp-1.6
+    with: pipeline:openshift-velero-plugin
+```
+
+## Troubleshooting
+
+| Symptom | Likely cause |
+|---------|-------------|
+| CI tests use an old image despite a recent plugin PR merge | Missing or incorrect `base_images` / `operator.substitutions` entry |
+| `base_images` import fails silently | The `tag` does not match the plugin repo's `to:` field |
+| Only some OCP versions are affected | A variant config file was not updated |
diff --git a/pkg/common/common.go b/pkg/common/common.go
index c13fb925fe6..86cca879076 100644
--- a/pkg/common/common.go
+++ b/pkg/common/common.go
@@ -65,6 +65,26 @@ var DefaultRestoreResourcePriorities = types.Priorities{
 	},
 }
 
+// CI image substitution: each image constant below has a corresponding
+// RELATED_IMAGE_* env var in config/manager/manager.yaml. For CI e2e tests to
+// use freshly promoted images (instead of waiting for the quay.io mirror to
+// sync), every image also needs a matching entry in the ci-operator config
+// files inside the openshift/release repository:
+//
+//  1. Add a "base_images" entry that imports the plugin image from the
+//     plugin repo's CI ImageStream (typically in the "konveyor" namespace).
+//     The tag in base_images MUST exactly match the "to:" field defined in
+//     the plugin repo's own ci-operator config in openshift/release.
+//
+//  2. Add an "operator.substitutions" entry that replaces the quay.io
+//     pullspec (used here as the default) with the CI base_images tag.
+//
+// Both entries must be added to EVERY variant config file under:
+//   ci-operator/config/openshift/oadp-operator/
+// (e.g. openshift-oadp-operator-oadp-1.6__4.22.yaml, …__4.23.yaml, etc.)
+//
+// See docs/ci-plugin-image-sync.md for the full step-by-step procedure.
+
 // Images
 const (
 	VeleroImage                  = "quay.io/konveyor/velero:oadp-1.6"