(the native one not the addon)

When a slide show is triggered it should autostart,
you shouldn't have to rely on the user knowing
that a second start button has to be pressed.

A slide show should start on the selected slide
from which the user launched the slide show
and not simply blindly restart from the beginning.
Actually yours does something even stranger, it
moves away from the launching slide, goes to
the end and then starts from the beginning.

A slide show should return to the slide on which
the user terminated the slide show and not simply
blindly return to the beginning. There are several
reasons why a user wishes to stop the sequence
which are totally overruled by the blind logic.

With more than a nod to all the above your slide
show is logically more of an album/gallerie show!
It should be therefore be trigged from the album
area not from each image.

Personal rant: for those apparently afflicted with
the need, or have, to use IE6 to slide view there
should be option to KILL all those incredibly passé
intensely annoying eFx (emphasis of the 'F') as all
they do is degrade the attention given to the
beauty of the collection of pixels being shown.
Normally I slaughter all that code/options at birth
but sometimes I forget and they get to leak out;~/

----best wishes, Robert