Join Date: Apr 2013
Location: Southern Indiana
Yours looks like a bay tobiano to me.
A simple rule of thumb is if the white crosses the spine anywhere from withers to tail head they are tobiano. Solid color (other than white of course) down the length of the spine is overo. This is the most basic explanation and there are variations of the overo pattern. Get them down pat in your mind and get used to recognizing those two patterns then move on to the more complicated things. I don't say that to be offensive just that once you those 2 patterns set in your mind it's easier to start understanding the other patterns, at least it worked that way for me.
Looking at lots of pictures of pinto horses can help too.