I had a client request recently to toggle an image button to a second image on mouse over. Under normal circumstances, this would not be difficult to accomplish since you can assign one image to the Normal state, and a different image to the Hover state, like so.
However, if you go this route, you can’t use container fields as the source for the images, but instead must make static file selections, like so:
Since this button would be appearing on dozens of layouts throughout a 20+ file solution, the client wanted to be able to store the two images in container fields, so an authorized user could easily swap in new container images (in browse mode, not layout mode) and have the changes ripple through their entire solution.
Demo Files: