Minus a third (nearly $1 billion) of its market cap in 5 days, Getty Images (GYI) is seeing the tangible effects of ...
1) supply replacement -- vast collections of photos online serve as alternative supply for people searching for photos to use/license.
2) demand displacement -- new use cases such as use of photos on blogs require new licenses such as royalty free or Creative Commons -- the terms of traditional rights managed licenses simply don't work for such use-cases, regardless of the price.
While more and more photos will be licensed and used (e.g. to decorate blog entries etc.) this additional demand will likely be satisfied by photos which are $1 or less, photos which are taken by eye-witnesses and immediately available (e.g. directly uploaded from cameraphones), and photos which are more readily found (e.g. users do image searches online from their favorite search engine).