Drat, Alex--you beat me to the Chernobyl motorcycle rides.
Terriblisma may be a fairly recent term, but the phenomenon it names has been explored most articulately by Susan Sontag. Her book "On Photography" (1977) is an exploration of the moral and aesthetic implications of being surrounded by photography, whether this renders the photographs more real than reality and depersonalizes the world.
She's recently published "Regarding the Pain of Others," a re-examination of the same ideas--the uses of images, their meanings--but in this case, directly related to the phenomenon of war, and if/how the ubiquity of images of suffering affect our abilty to sympathise, and to act.
http://www.susansontag.com/