This is not really a visualization tool at all -- it just allows an image to be displayed as a background to the layers. Generally the image will be some form of map that corresponds to the data in the model. Because the pixel pitch of the image may not correspond to the position data in the model, the properties dialogue allows an offset and scale to be set for the image display. Thus the tool also allows the whole layer display to be annotated with small images.
When the tool is selected, a file selection dialogue appears for choosing the image file, which immediately displays. Its offset and scale are then adjusted via its properties dialogue. To change the image, delete the layer and add a new one.
In: Contents >> Running models >> Working with helpers >> Layer tool