Hoy,
Well, I like the arrows as it is a visual clue that there is something "further". I thinks images are ideal hotspot for facts and information, but not to indicate the user he can see another place away. My opinion ...
The point is to find the correct look and feel for the arrow, now (as for the entire GUI)
Aside of that, your Alps tour is great and the buttons fit well to the 5 shots... I have a 33 shots tour in my bag and this Hampi is 95 shots I can't image the number of images and the size of them Even if I have seen here around someone that make "small planets" panel to link between his shots. Pretty good idea and nice look. But I still prefer the arrows.
I'm used with Myst game
Anoril