Sheesh! I found the answer buried in the fine print of the Icon constructor, sort of.
If a version cannot be found that exactly matches the size, the closest match is used It's true, for example if I ask for a 48x48 which isn't there I get a 32x32 instead as a fallback when I inspect the Width and Height properties. So it looks like you can't enumerate the Icon's image contents, you have to construct a new one for each image you'd like, which it rather crappy in lieu of a proper technique. Greg