One of the problems to be addressed for adaptive treatment paradigms is the need to visualize and interact with deformable vector fields (DVFs). While a number of techniques exist for visualizing vector fields, such as heat maps and hedgehog plots, a simple technique is to allow interactive morphing to examine how the vector field is altering the target image to match the source.
This is a very old MFC program that allows loading two different PNG images, and then provides a slider to morph back and forth between them.
Note that currently the two images that can be loaded through File > Open Images... must have the same width/height, and are both required to be in .BMP format.
First is a video of Grumpy to Hedgy:
And this, slightly more clinically relevent example, shows one MR slice being morphed on to another one: