The whole original input layout is used as a dynamic overlay by default. To remove parts of the layout from the dynamic overlay, you must define fields and specify how the content in the fields should be handled. A field can contain text segments, images and graphical objects.
To remove a part of a text segment, you draw a rectangle around the part to remove. Parts of an image or graphical object can not be removed. You must draw a rectangle around the entire object.
In this example, you have a page containing an image surrounded by text segments and graphical objects. You want to use just the image as a dynamic overlay.