Why is there only 1 image in this set?
Or is it just my laptop who isnt loading?
(darn ... lost my initial reply, so this one is a bit shorter than intended)
Why: probably because there was no general AZ sanity check on the source CSS data.
There are also cases with 2,3,4 frame. And 5 and 25 frames, although those only show them self in Talk.
Just mark the single frame cases as [Bad image set] in the classifying page. And move to the next set.
In 2 and 3 frame case its still possible to spot a potential asteroid. If you like to try, that is.
(technically you could also do so with a single frame set, but that's a other story.)
Real image loading failures are really, really rare. switching between normal and inverted view is usually the way to spot those cases.