Just how crazy can CarrierWave get?

Hi,

I'm really impressed with CarrierWave, especially how it creates multiple versions of each file you upload.  For example, when I upload an icon image, I can use RMagick to create 3 different sizes.

I was wondering whether I could get really crazy here.  Does anyone have an idea to perhaps create an image on the fly using the originally uploaded image?  For example, the uploaded image with a red X and circle translucent over it.

Any thoughts appreciated.