Don't load the Likes iframe until a slide is visible or is one of the next or previous slides.
Don't load images in the carousel until the slide is visible or one of the next or previous slides.
Be smarter about deciding which slide is next or previous.
Round any numbers used for positioning or sizing in CSS.
Resize the carousel right after opening; this fixes issues with the theme's CSS for the comment form overriding Carousel's. (e.g., Twenty Thirteen)
Remove unused code.
Prevent 'method' from being global and whitespace/comment.
A better lazy-loader for images:

When the slides are created, use the image from the in-page gallery as a low-res placeholder. If that image is as big as the eventual high-res image needs to be, don't load it again.
Hide the next/prev buttons if they're not needed.
Some optimizations for 1, 2, and 3-image galleries.
Replace the per-second check for a reopened carousel with a hashchange event.