Website Design – Where does the illustration have to go on this wired UF?

Generally, the additional illustrations do not go to the wire illustrations, they are rather introduced in the visual design phase.

If you really want illustrations to be added in wired structures, then it should be behind the text field, obviously not above it. In the wireframe phase, the designer focuses primarily on the part of the interaction or the user interface involved in the user interaction.

Generally, there are several types of wired structures. You can find better ideas by reading this article