Your favorite image in a horror film?

Clarice Starling walks into the bathroom of Buffalo Bill's lair and sees a decomposing body in the tub. That's the last thing she sees before he kills the lights and she's left fumbling around in complete darkness with Bill watching her through his night vision goggles. That scared the shit outta me the first time I saw it.

[deleted]

In my favorite movie of ALL time :
The Thing From Another World 1951 -
Crew spread out to the edges of the dimensions of the thing that crashed into the ice- it forms a perfect circle. They realize they have a real UFO! Chills me every single time!

It's so hard to choose but the first that comes to mind is Freddy Krueger walking through the alley with the super long arms. (Lots of great images throughout the whole Nightmare on Elm Street series whether or not they're great as films beyond the first: Special mention to Freddy emerging out of Jesse's body and tossing it away in Pt.2 and the tower/puppetry scene in Dream Warriors.)

Here are a few others off the cuff:
• The living shadows in Carl Dreyer' Vampyr (the whole movie is delicious though)
• Frankenstein's monster making his entrance backwards and turning around in Frankenstein (1931)
• Blood in the elevator in The Shining
• The opening, and dancing corpse in Evil Dead 2, among many others, and the final stop motion sequence in Evil Dead
• If you're willing to consider Valerie and Her Week of Wonders a horror film, the whole damn thing
• The first appearance of the cthulhu thing in Possession
• The woman on the lake in The Innocents (1961)
• The stone piles in The Blair Witch Project
• The entirety of Tetsuo the Iron Man
• Begotten
• Bees in the mouth in Candyman
• The beetle/nail maypole in The Wicker Man
• The appearance of Satan in El Dia de la Bestia
• The first victim crashing through the stained glass ceiling in Suspiria
• The sheet attacking Nurse Keating in The Exorcist III
• Rob Bottin's rabbit trick/creature puppets in The Twilight Zone movie
• Belial trashing the hotel room in Basket Case LOL

I'll also say that possibly the image that disturbed and haunted me more than any other as a kid was the dead woman in the bath in The Shining.

And scariest horror image in a non-horror movie = Large Marge in Pee Wee's Big Adventure.

And also, thinking about this I'm realizing that actually most of my favorite moments in horror movies are atmospheres and convergences of elements working together rather than an image itself, though I think of being into horror visually.

Great choice, OP. As for Psycho II, I agree that Psycho is the better film, but I would actually say that PII is pretty well masterful! It's a great movie, and definitely one of the best horror sequels. It holds its own right next to the original in most ways.