Could one have several images in one "image node"?

I've tried image.module instead of my image-enhanced CCK new content types, to allow users to add images to my site with the simple "Upload" button option.

What I want is: User upload images, images have three sizes - thumbnail in teaser, medum in full node, and original size - all seen withing a page (no links straight to image.jpg). Image.module does this exactly.
I also want to use watermark - image node works well with this.

Here's my catch - I want to have at least three images per image node. Could this ever be possible?

As I understand it, each image becomes a separate node. I have 600 current "Image enhanced" CCK style posts, each with at least 3 images in them, if I changed these to "image" type, then I'd be making roughly 1800 new nodes?