The fact that there is a `dispose()` method to be called is easily missed, as people tend to look for a method called `close()`, or assume that resources only need to get closed when they support try-with-resource. As a result, there is a risk of keeping resources opened longer than needed (or even run into a resource leak with long running processes) as the user cannot use try-with-resources currently.

This is not a big change, but it is useful for those working with ImageIO.