Once you have selected one or more objects, be it text or line-art or pixel images, you can hide the selection. You may wish to do this, for example, if you wish to edit objects which are difficult to select because they are in part or completely covered by other objects. Hidden objects will not be visible in wireframe view.
You can hide one object at a time and make hidden objects all at once visible again.
See also Viewing a PDF document in wireframe view.