In a corporate environment where you care about such things, you really want to disable the functionality of the user setting the background in the operating system, not in a specific application. Otherwise, you’re going to have to track down every application that includes this functionality, figure out how to disable it it in that application, and find a way to apply that change to every PC. (Microsoft’s Photos app, for example, can set pictures as either background or lock screen.)
In a corporate environment where you care about such things, you really want to disable the functionality of the user setting the background in the operating system, not in a specific application. Otherwise, you’re going to have to track down every application that includes this functionality, figure out how to disable it it in that application, and find a way to apply that change to every PC. (Microsoft’s Photos app, for example, can set pictures as either background or lock screen.)