Hale-Bopp
Thumbnail gallery.
http://www.astro.umd.edu/~ma/images/index.html

Comet Shoemaker-Levy 9 Collision with Jupiter
Various pictures and information about this particular incident.
http://seds.lpl.arizona.edu/sl9/sl9.html

Jim Scotti's Comet page
Images of comets you've never heard of.
http://pirlwww.lpl.arizona.edu/~jscotti/comets.html

SL-9 and Jupiter
Offers several images of comets and planets.
http://www.eso.org/outreach/info-events/sl9/

SL-9 and Jupiter
Images from ESO
http://www.eso.org/outreach/info-events/sl9/images/