I noticed in doing some of my other testing, that the Wizard uses a graphic from the module as the background image, with a list of the steps superimposed on top of it.
Furthermore, it seems that the image is a bit de-saturated.
For many modules, this may work fine, but there are modules which have a sufficiently dark image that the text indicating the steps to be undertaken by the wizard is not really visible.
For example the Ambush! mod has a black border that really doesn’t work with this. The default Vassal background image allows the text to be read, but the background is sufficiently busy that it doesn’t make it very prominent. It also makes it more difficult to immediately notice that these are the wizard steps and not some text associated with the main graphic.