Oh, I like ponies in outdoor settings.
In the last two pics she looks like she's glowing, it gives her a slightly eerie look. I'm sure she's a garden fairy or some other magical creature!
Have the photos gone through any kind of postediting? I think you could try cropping them a little, that would help in drawing the viewer's attention to the pony. Just play around, perhaps, and see what gives you the most interesting results? I'm not sure about other programmes but GIMP has helpful grids (thirds & the golden rule) that often make cropping images easier. Of course you may decide to disregard all such rules of composition and go with your own artistic vision.