First I'll say that the head looks a bit too big in the first picture. Also, the back ear is a bit short. It should be longer horizontally than the front one, because the front one is bent, while the back one is (or should be) straight.

As for the background, it's alright, but her expression doesn't really seem to match up for such a nice day. She seems surprised at someone's or something's presence, but there isn't anything else to hint at this. When doing a shot which is meant to represent an emotion, it's often good to attempt to inspire that emotion through the help of the environment.

Now, for the second piece, I'll start by saying that the ghost thing looks a lot like the Sith Lord Marko Ragnos from Jedi Knight Academy... The ghost looks very spirit-like, so I think that worked out.

As for the character, I can't really see very much of (her?) though I presume she's robbing a tomb or something? The environment doesn't really help explain the situation, and the object she's holding seems to resemble a tricorder or a grappling hook. Neither of which seem to explain the situation.

Now, if it's a gun, it should be held less pointed out, as I presume you wouldn't want to accidentaly fire at a wall and alert Mr Ghosty. She doesn't seem to be holding it like it's very dangerous, so I presume it must be a scanner of some sort.

If you're going for a Ghost-busters thing here, it's on the right track, but I'd reccomend adding some more environment and maybe show off more of the character's... scanner thing...

How was that Radium?