When floating images are placed in a header or footer, and are positioned outside of the text editor's area, they are not visualized. 

MS Word visualizes such images as slightly grayed out (similar to watermarks) in normal mode, and always visualizes them in Header/Footer edit mode.

This item is merged with another one concerning the same issue. Please, follow the item at https://feedback.telerik.com/Project/143/Feedback/Details/174624 .