An object-oriented framework for image registration, fusion, and visualization was developed based on the classic model-view-controller paradigm. The framework employs many design patterns to facilitate legacy code reuse, manage software complexity, and enhance the maintainability and portability of the framework. Three sample applications built atop of this framework are illustrated to show the effectiveness of this framework: the first one is for volume image grouping and resampling, the second one is for 2D registration and fusion, and the last one is for visualization of single images as well as registered volume images.