How to place a PNG image into a scene?

I have placed this PNG image of a footy field onto a plane and then inserted it 1m above the terrain. How do I lower it so it merges with the terrain (I would be willing to let it hover 1mm above the ground if necessary, and how do I remove the black exterior of the image? Thanks.

 

I have discovered both solutions (even though the image has to hover above the terrain.
1. Set the plane to be 0.01m above the ground.
2. Change the material of the PNG file from Opaque to Cutout.