No UI feedback for loading images

[wmassingham]

Currently there's no feedback to indicate that an image is still loading. If you hit "back" a few times, for example, you'll still be seeing the same image, with no indication that this is wrong. (Should probably also preload the next and previous image, too.)

[dataxpress]

seconding this one - especially for the case where you're clicking through the images and nothing has changed, and it's hard to tell if nothing has changed because the next picture was identical (because Randall would do that) or because it hasn't loaded yet. You kind of also have to play the "spot the difference" game to see if it's loaded.

I recommend adding a loading spinner above the image, and have it stay until image is loaded OR at least 0.1 seconds, whichever is longer. A spinner that flashes too quickly is almost as aggravating as no spinner at all.

I could start on a pull request for this, though my Javascript knowledge is pre-jQuery so it might be rough