Which area this feature is related to?

/area documentation

Which area is this documentation change is related to?

/area api

Issue details

What mistake did you find / what is missing in the documentation?
The existing imageName field in the image component only has a brief field description. Based on the discussion on the community call on 11/14 (see the recording https://drive.google.com/file/d/1XLTdizST_LeoKpF7xw4Q9k__6LoXKCmo/view?usp=sharing for details), we need to clarify how the imageName field is set and handled by the tools.

Summary of the change:

1. The user can specify the imageName with either a full URL or a relative location of the image within an image registry to store the built image.
2. If a relative location is being used, the tools will have their own way to find out the image registry location (e.g. detection or user input). After the image component is built, it will automatically replace the correct image location in memory so that it can be used by an image container or the kubernetes component for deploying the image.
3. If a full URL is used, the tools will not replace it with the automatically generated URL and will use the full URL to store the built image.