When I import a 16x16 .png texture I created into Unity it becomes really low quality. When I open it in paint.NET it is high quality. (Creating a game with minecraft-like textures).
Why is this? Thanks.
The quality is fine considering the texture you're using. The actual question seems to be "how do I turn off bilinear filtering", in which case the answer is to change the texture's Filter Mode from Bilinear to Point.