Alterations to a website

I have an urgent requirement to complete a website started by another contractor from GAT, the project was completed and my client decides at the last minute to change the colour in the background, which includes a wallpaper style jpg background that is the same on every page in the site. The previous designer, nicely sliced up the background, but there are many slices (approx 24) and there's 9 pages. See images attached, the current website is red and we need to change it to white and black marble.