Are you talking about runtime as in while running on the Xbox? If so, no. But if you are talking about as part of your development process, then you could add a special content pipeline class, or at the most basic, a simple custom build step that runs a tool that updates image files needed.
Custom build steps allow you to specify the output files that should be checked to see if they need to be updated or not. You'll probably need a directory with standard naming schemes for the individual frames of an animated sprite, and a text file with the properties of the spritesheet to be parsed by your tool and also double checked for being up-to-date by MSBuild.
Check out the Spritesheet Packer by Nick Gravelyn for the example of modifying image data and outputting it. It's not what you're looking for, but it covers similar ground.