Vanilla is a product of Lussumo:
Documentation and Support.
And I'm sure someone skilled with some php or whatever programming skills could whip up something similar fairly easily so it doesn't have to be Wordpress based.
The image (..) is cut off at the bottom
64k-per-screen limit makes Kindle comics difficult. Josh Fialkov did one, as I recall.
Which tells me that if Amazon is "holding" your color files, a color version of the Kindle isn't far off.
From where I sit a big problem with comics systems is that they use so little text that it's hard to get the search engines to understand there's any content there. In any other kind of web site you'll get most of your traffic from searches. But anything that's mainly graphics is hard to index and hard to find.
That's indeed a problem, though I don't know how big a problem it really is.
I've got into the habit of using the accompanying blog post for additional information and stuff, although I'm not a fan of anything that interrupts your reading flow. But it helps make the site more search-friendly, and the searchers hopefully get something more out of it than just a mention of the words they searched for.