Knightmare inspired creations from the community.
I've not tried drawing much on a computer for quite a while, but Knightmare-themed smilies sounds like fun, and I generally have more success with small numbers of pixels. Don't hold your breath, though. I'm notoriously bad at getting around to doing things.
The difficulty with our smilies is the dark background. Most smilies seem to be designed for use on a white background and are anti-aliased to match. When they get moved to a dark background you end up with annoying white pixels around the edges.
If they are PNGs then PNG's transparency features should sort that out. Make the edge pixels semi-transparent instead of anti-aliased to a specific colour, and they'll blend in with any background. The only possible issue is browser support. PNG feature support was definitely an issue a few years ago, but I imagine they're mostly OK, if not perfect, these days.