That is really a unique mark on her rump. Looks like a check mark.
Yeah, now that you mention it, it does. She's got more white than that but you can't see it for the saddle. I didn't think she was taller than my old gelding, Tennessee, but she either is or my legs are getting shorter because I had to find a hill to get up on her. You can see in the picture of me standing beside her that the stirrup is about even with my elbow, and I'm 5'7". The guys were laughing at me, but they have to do it too. Their horses aren't all that tall, they're just old-er. I can't make too much run of them either though coz I'm headed that way myself. ;o)