How to add an image to the menu without a plugin?

Question

WordPress

For example, like here https://stuff-shop.com/

I found a way here https://slicejack.com/create-fully-custom-wordpres... , but the sidebar does not appear in the admin panel.
I assume that the walker, before closing the ul, somehow make an area for the picture.
With the dynamic addition of widgets, as in the method found, it would be nice.

Answer 1

Briefly:
You take a picture and throw it into media files, copy the location link (it's in the same place)
Go to the theme settings - additional styles
Create a class for example .menuicon
Specify the path to the picture (the link you copied at the beginning) and add it so that it does not repeat and the size is for example 30px
You go to the menu editor, create an arbitrary one by adding it to the menu, open it and add a link, and at the bottom in the classes you insert the class that you created
Everything!