Post Build Low Quality Issue

Hey guys, I'm fairly new to unity, and I just finished my first game. I've been attempting to build my game, but every time I build the game, the overall quality of the terrain itself is significantly lowered. I don't know how else to explain it so I will just attach pictures

When I am in the editor, the rocks look just fine, but once i build the game, they look terrible. I'm using full resolution for the texture quality. I'm not sure how else to explain this problem. Thanks for helping out.