Icons in TabbedPage

I am struggling to get icons showing up in my TabbedPage. The icon property of the Page is a string, so I cannot use the ImageSource.FromFile.

Now for IOS i noticed I can set the ResourceId for the icon image which will work, but how does this work with retina @2x, etc?

Also it seems there is a bug in xamarin form where you set the resource ID for the resources, it works when you build it, but when you clean/rebuild it clears it out which is very frustrating.

What is the best way to set the Icon property for it to be Cross device compatible?

Thanks