Maptool + Converting maps from WOG to SOD.

Guys, can anyone tell me: how do you make an image (in the scenario itself, in the editor) in the middle of the map?

It's not that simple, you'll have to find a workaround:)
For example, create the image and place it in the center of an image the size of the map you need. Then, create a map where the image is only in the center, and the rest is empty territory, which you'll have to edit in the editor.