I should be able to set Preferred Image Size when I create a Photo Property

Summary: This is one symptom of a much more general problem, that it is extremely awkward to deal with most meta-Properties. Currently, you have to find and edit the Property using the old-fashioned Editor. You should be prompted for this when you say that you're creating a Photo Property.

I think I'll using this as a forcing function for a terribly-needed general enhancement. Types should be able to declare optional-but--often-useful meta-Properties that are relevant to them. If one of these exists, when the user is creating a Property and selects the Type, we should adjust the form to display these meta-Properties, and optionally add them.