I had discovered widgetkit when I needed a great mp3 player that did not rely on flash.  Widgetkit ALSO provides a pretty friendly slideshow solution that does not combine cropping and resizing as the ckslideshow extension does.

CK Slideshow might be a good solution if your slide images won’t suffer from being cropped — the smaller images delivered on a mobile device will be a vertical slice of your horizontal banner image, rather than just a proportionately reduced banner.    In some cases this would be a better solution — but banner images would have to have good content in the middle of the banner image and often that is NOT the composition we’d prefer for the larger images.

Tradeoffs!