Map resources for online DM/GMing?

Hey guys, I am putting together a homebrew campaign and need some help. I have the world map all set up. I am not sure where to get "tiles" like squares of a seamless grass texture, trees, pathways, and so on that are all the same art style that I can make "combat ready" maps with. By "combat ready" I mean maps that the characters can move around on square by square and do stuff.

Does anyone know of where I can get just general environmental tiles to be able to make the small maps with? I will be using Roll20 by the way to DM.

Quickest: Do an image search for "battle map" or "rpg battle map". You can also add in if there's specific things you're looking for. I prefer using the Bing image search to Google's, because I like the way it lays things out. You'll find plenty of maps with squares. And since a lot of them use the same software, there will be plenty that have a similar style.

Best: The Cartographers's guild. You'll have to search for it, because I just signed up and aren't allowed to post links. But it's great.