Another Yafaray question - image background

[qewer3322]

So I am trying to get better at rendering things using Yafaray. I looked up some UV mapping tutorials on Youtube and checked Yafaray's website for more information and this is one of my latest renders:



It is looking pretty nice but how can I get rid of the lines (edges) showing up on the render? And how can I add an image as a background?

I tried looking up for the background but Yafaray's website shows how to do it on Blender. I couldn't find one about the W3D plugin.