Hehe, old Sanssouci up in Potsdam. But why is it at an angle? Last time I was there, the building didn't have a slope. Besides, I should imagine true "lovers" to share one umbrella, not walk with one each at one metre's distance.
I was kidding about the slope. Why not correct the angle? If you don't want to waste too much money and time on buying and learning Photoshop CS, you can either have a look at Photoshop Lightroom (which is relatively cheap and easy to use, producing great results as well) or download the free and open source Gimp [link]