How to manage graphics for Package Apps?

Greetings respected colleagues,

I working with the new application packaging stuff for a new release of a mature app. I'm running into what I think are simply "can't find the documentation" issues.

#1 On the Main Package App dialog there's a "Select screenshot" button/drop area. What can we put there? All the png's I've dropped in or selected are ignored. I suspect they are too big or it doesn't like png's but I can't find anything on limitations of formats and size.

#2 Is it possible to use my own icon for my app? If so how do I set it? Can't seem to find anything about it but all the prepackaged apps have custom icons.

In general the application installer works pretty well and while it did require a few changes to the application they weren't unreasonable at all.

Thanks,

Joe