How big?
 

Here is some pictures I took this morning. How big do you think this buck is? I hope they are 140 inches or bigger.

I'd say he's around that size. It always seems like the bigger the diameter of the tree the bigger the deer. Never watched a small buck rub on larger trees. Especially when a rub is tall like that you know that the antlers are able to rub a lot more surface area and reach higher up on the tree than a smaller buck can.

Good luck on hunting him down!

Ive seen a 14inch 8 point tear up tree's that size, now when you start getting them and big cedar trees and oak tree's then you have a monster's area.

Flat out impossible to tell by the pictures. I'd be looking for distance of tine tics above the main rub and damage to adjacent trees, as well as the back side of the main rubbing. From these you can get a pretty good indication of tine/main beam length, width.