It doesn't really look like the frog is on the ground/wall/roof/swimming pool. To be honest, I'm kind of lost when I try to think of much critique for it. I mean for the most part you got what you were trying to do and you did it right..I just don't like the image. :p
Hmmm... I see what you mean. There is a bit too much shadow under the left foot of the frog, making it look like it's suspended there. I'll see what I can do to fix it.
Here was the original, just for the sake of showing it: