If you want to float you menu on top of the image using the new Top and Bottom menu settings here are a few tips and settings to get you started.
It sounds counter intuitive but the amount of float the menu has (how far up or down it appears on the image) is determined by the Top or Bottom Margin in the Website Container section of Layout.
Once you set a margin there (lets use 50 on the Top Margin for this example) you will offset the image (under Layout—>Menu—>Menu Offset) an amount equal to the Top Margin (50) plus the Menu Background Width (45) = 95.
If you want the image to show through the menu you can adjust the Background Transparency (under Menu) to be less than 1.
One more important tip. If you have sub menu items that open when you click a menu item (i.e. clicking Portfolio opens New Work below it) you will want to set the Vertical Text Position (under Menu again) to Top so when they open the menu text doesn’t move.