Here's an interesting new service: Tourist Remover will take the tourists out of your pictures. If you've got a series of sequential images of essentially the same shot, you can submit them all to the Tourist Remover service and they'll compare the images and take out the transient features.
It's free, but they're willing to take your money if you want better service. Might be worth a look.
Kudos to Boing Boing for mentioning this.
Technorati Tags: digital images
