review: Update README with images sections

tests/airgapped/README.md

@@ -10,6 +10,20 @@ For running the tests we expect an environment that can:
 We need docker to pull all the images necessary and push them to the airgapped
 lxc container.
 
+## Update testing images
+
+The scripts that setup and test the airgapped environment will also need to load
+a list of predefined images, for running tests in the airgapped environment.
+
+Every release has its own set of images. If you are creating a new release, you'll
+need to create a new directory and the corresponding images file.
+
+You can find such files under `tests/airgapped/<release>/testing-images.txt`
+
+To understand how those image are being used by the tests, please take a look
+at the
+[Test Charmed Kubeflow components in airgapped](#test-charmed-kubeflow-components-in-airgapped)
+
 ## Setup the environment
 
 We've prepared some scripts for setting up the environment
@@ -133,8 +147,5 @@ To test Charmed Kubeflow components in airgapped, follow the instructions in the
 * [Pipelines](./pipelines/README.md)
 * [Training Operator](./training/README.md)
 
-You will also need to ensure the airgap setup script is including the file that contains the airgap
-testing images. For a new release, we'll need to create a new dedicated file with the images needed
-for airgap testing the new release.
-
-Such images files are usually located under `tests/airgapped/ckf-X.Y-testing-images.txt`.
+Make sure to follow the first part of this guide on updating the oci images that need to be present
+in the airgapped cluster in order to execute tests.