on to the picture i have seen the original (but did not really study it) so it looks very true to the original pice.
love details like "winter wrap up co-ordinating (i whould have done "-stion" but if that a trow back to the oringinal i take it back) committee" and the fact that AJs hair ribbion is the same couler sceam as the bandana.
and the cutie mark on the collar.
love the shadeing and nice hair detail.
and finaly love the captured "strong girl" (or what ever you call it) essance.
I imagine that once the ponies permeate general culture a bit more, we'll start seeing real motivational posters with the ponies on them. This may not necessarily be a good thing though. I remember a large number of sad-looking Garfield posters, with tepid taglines like "Read a Book", covering the walls of my former high school. 0_0
I really like how the colors have been blended with soft shadows. The similarity to the original painting style is a good textural match-up to AppleJack's personality. The movement of her cutie mark is quite clever too.