The idea behind it switching to the next image is to promote voting. If it stay'd on the same image after a vote you would have to goto the gallery to see the next image, which would be a pain for alot of users.
I'm just finishing off writing an image categorizer that will let people only view different categories (selected options under your account, at your choosing).
You can also 'vote' for a image to be put into a category and that wont move you onto the next image. Also an option will be given to uploaders to put their images in a category (which you wont HAVE to fill in and can let the users decide what category the image will fall into).
I'm also thinking of adding some rules to users accounts that will let them change how the site acts. One such rule can be as you asked, having it not move onto the next image after a vote. But it's still an idea floating around in my head.
I'm very interested in seeing how well the categorizer will work and if users adapt it in the use of the site.
My only suggestion is to get quick with the escape key after you vote for an image so it stops loading the next image