OK, I finally had some time play around with the masks. I had supposed, because of the term "mask" that the masks in iMaginator and Ron's masks were already transparent, but upon closer observation, Ron's were JPG, and therefore, not transparent.
I used iMaginator's "Mask by Color" on each of Ron Bishop's masks to make the white part transparent, and exported them as PNG files. I think they make excellent masks or frames that you can place over a photograph, masking the edges, and having the center show through.
They work great in iMaginator and in Create. You can get some really wild results by combining 2 or more masks for a composite effect.
You can download all 26 (19MB) from my iDisk Public Folder (rogerdye). I assume since Ron originally offered them in the Forum, that he won't mind my passing along my variations on his work