Placing fixed position art behind the content area

I would like to place a fixed JPG slice of art that floats IN THE BACKGROUND under all the articles and headlines midway down the content area on just the home page. I have looked at sparky_inner .contentrow in css but it would apply to every page. Maybe a ghosted image of water or a map. Unsure about the art just a tint of an item that goes across the entire screen.

Alternately can i have a new row in the sparky layout that has say, content from K2 in it on subpages without the art slice, by using say a new css class. i.e. content2row and set up a row that is used only on subpages, while the home page remains as contentrow class ?

I only have ONE content tab to insert though.
Please let me know how this might be possible. I can edit the css as needed.

Layout row will appear if there are some modules active for that page in it. You can set css class for each row you put in layout.