Images in the official documentation

Hi %,

I am working with PostgreSQL documentation quite a few years now and I am almost happy. What I think is completely missing (especially if you compare to commercial product documentation) are pictures that illustrate a topic, e.g. the relation of instance->database->user/role->schema->objects.

Is there an agreement not to include that pictures for any reason? I can not promise that I find time for that in the near future but if that will be appreciated I am willing to spend time on that to make the documentation even better.

Regards

Daniel