The issue isn't so much that its not detecting the change, but rather that it's detecting other biomes as it smooths the transition. For example, when I go from the yellow to the red, it detects orange and delivers that biome. I will try what you suggest, but I'm concerned that I'm going to end up having to spend a lot of time creating a color list where no two bordering biomes create a color similar to another biome. Also, PNG compression is lossless, so I don't think that plays a factor here.