Design Patterns Question: Different types of filters for "Image Processor"

This is a strictly theoretical, architectural design patterns question:

Say we want to design a system that allows for different kinds of filters to be applied to images. In other words, an image processor.

What kind of design would you use?

I was thinking of the following: some kind of Factory for creating the concrete classes that extend/implement an abstract Filter object.

I'd appreciate any ideas about this job interview question.

(Another idea: template method for the filtering).