[DustyPorViva]

First off, please don't use BMP's. They're huge in size for such a small image, try PNG/GIF next time.
Anyways, on to the image. This looks more like a large painting/sig thing than actual tiles. The tiles themselves, well the tree's, are way too blurry to be presentable in a game. I don't think they need outlines, but I think the outline of the tree's themselves need to be cleaned up and not blended in with the surroundings. Overall, just sharper.