This week's pic is of Eliza Lindstrom and her appendix gelding Baylee. This was taken at the Wasatch Pony Club Pumpkin Event in 2013, during the dressage phase. They were competing in the grasshopper division.
I'm loving this pic for a lot of reasons. First, Baylee is in a nice forward trot, is straight on the centerline, and is alert and attentive. I like that Eliza hasn't forced him into a "frame", but instead is letting him move freely forward and use his body as is expected in the introductory level tests.
Eliza's position is also great. If you were to draw a straight line down the side of her body, you could see that she has the correct position because it would go through her ear-shoulder-hip-heel. She also has a soft contact with the bit, and is sitting correctly in the saddle with her weight on her seat bones and pubic bone.