Wow - your answers just revealed something surprising! I didn't realize that there were so many images created for each original image. Here are some follow on questions:
1) Each image I uploaded has ten images associated with it; a copy of the original and nine "c & p" versions. Why does PowerGallery create so many versions when the files are "uploaded"? Isn't this a huge waste of storage space? Can I instruct PowerGallery to only generate what is needed for the particular Gallery I select?
2) If all these versions are already created, why is any processing needed if I want to change the Gallery style? Or is your instruction to "process an 'empty' watermark" only needed if I have added a new size to the code?
3) Since we have all of these versions of each file, is there any reason I can't delete (from the server) the files that I originally uploaded that were processed by PowerGallery when I selected a Gallery style?