I noticed that when you set a wallpaper, image quality is not the same as the original ... a bit more blurry, and you get some artifacts.
While this is not dramatic, it annoys me, is there some method to let not just "compress" the image?
Tried with the same image in various formats (jpg, png), and it allways shows the same artifacts.
The example (zoom in your browser to see more detail):
Here is the original wallpaper
And here is the capture of how it gets artifacts when applied to background :
Notice the white lines around and under the birds?