Hi Sander,
This is the intended behavior. I guess you expected this answer, didn't you?
The
Window > Next Image command is intended to swap between two images quickly, without having to use the mouse. Its primary purpose is to help during dynamic processes that work with two images, as DynamicAlignment, or to toggle between two versions (as before/after versions) of the same image.
The
Window > Send Active Image Window to Back command works as you expect, cycling throughout the whole set of open images.
I'd prefer the standard windows behavior of alt-w plus a number to grab the numbered image.
As you know, there is the View Selector docked at the bottom left corner by default, which allows you to select any view. In addition, you can use the View Explorer to navigate through all images and their defined previews as a tree structure.
I have something very nice on the drawing board that will work as an image navigator (and more). It is complex and still requires a lot of work though... patience!