Nice and intuitive, and works like a charm. Some small issues:
- layout of the widget in the WP backend is cluttered in W7+Firefox: the buttons don't align well;
- the slider isn't placed in a <p> tag, so I have to repeat all styling on a
.widget p on
- I'm really missing a 'swipe' transition option -- a 'slide in' where simultaneously the original image slides out.