# Define additional images

This topic describes how to define additional images to be included in the `.airgap` bundle for a release.

## Overview

Air gap bundles (`.airgap`) contain the images needed to install and run a single release of your application in _air gap_ environments with no outbound internet access.

When building the `.airgap` bundle for a release, the Replicated Vendor Portal finds and includes all images defined in the Pod specs for the release. During installation or upgrade, KOTS retags images from the `.airgap` bundle and pushes them to the registry configured in KOTS.

Any required images that are _not_ defined in your application manifests must be listed in the `additionalImages` attribute of the KOTS Application custom resource. This ensures that the images are included in the `.airgap` bundle for the release.

## Define additional images for air gap bundles

KOTS supports including the following types of images in the `additionalImages` field:

* Public images referenced by the docker pullable image name.
* Images pushed to a private registry that was configured in the Vendor Portal, referenced by the docker-pullable, upstream image name. For more information about configuring private registries, see [Add and Manage External Registries](/vendor/packaging-private-images).
     :::note
     If you use the [Replicated proxy registry](/vendor/private-images-about) for online (internet-connected) installations, be sure to use the _upstream_ image name in the `additionalImages` field, rather than referencing the location of the image at `proxy.replicated.com`.
     :::
* Images pushed to the Replicated registry referenced by the `registry.replicated.com` name.

The following example demonstrates adding multiple images to `additionalImages`:

```yaml
apiVersion: kots.io/v1beta1
kind: Application
metadata:
  name: my-app
spec:
  additionalImages:
    - elasticsearch:7.6.0
    - quay.io/orgname/private-image:v1.2.3
    - registry.replicated.com/my-operator/my-private-image:abd123f
```