Next time, I suggest submitting your image at the largest size allowed. See this link (it might help even if you don't use Photoshop.)
Nice blur on the moving pinwheel, while keeping the kids in focus.
it's nice seeing cause and effect within one image. and I like the nostalgic (for me) 70's style natural lighting. as casual as this seems, every element in it adds to the story. 8
I really like this photo. The little boy in the back is so cute! I also like the splash of color and the spinning softens them (the colors) so nicely. I'm sure you are getting tons of "too small" and the votes you are receiving are reflecting that. I'm not going to do that and will give you a 9. Don't be discouraged if you are scoring low, it isn't because of the photo, only because of the size...(in my humble opinion).