For a cluster that you manage with a single image, you can edit the image at any time to add, remove, or update an image element. For example, you can edit the image to update the vendor add-on version that it includes, to add or remove a driver, to upgrade the ESXi version in the image, and so on.
Working with Drafts
When you edit an image, vSphere Lifecycle Manager saves the working copy of the image as a draft. The draft is an edited but unsaved version of an image. If you edit an image but for some reason you do not save the new image set-up, when you restart editing the image, you can use the saved draft version as a starting point or you can altogether discard the changes that you previously made.
You can validate an image draft before you save it. Validation checks whether the image is correct and complete. During validation, vSphere Lifecycle Manager checks for missing dependencies and conflicting components. In case of issues, vSphere Lifecycle Manager returns messages with information about the existing issues. You must resolve all issues before you can save the image.