Nivo Slider stuttering

I just tried installing Nivo slider and did the whole thing with adding code to the header and all, and it sort of works, but it’s almost like it’s stuttering and getting stuck.

An image will load, but then the next image loads like 20px lower than it, then when the next image tries to load it stutters, speeds up, and reverts right back to the first image… any ideas?

Take a look: http://sarahnicklin.com/test/

Thanks!