Sometimes you don't get what you pay for. There are many free image viewers that absolutely rock; check out Toyviewer and CocoViewX for a by no means complete sampling of what's available.

Slideshow Magic is nice, but is it really worth the money? If I were going to pay for an app that does slideshows, I'd buy GraphicConverter X (actually I did buy it). It does slide shows plus all the image editing and processing you need this side of Photoshop. And it's from an established firm, so you know it will be supported for many years to come.

As far as a light weight, fast, and full featured slide show application with light editing and processing capability, ToyViewer flat-out rocks. Your pr0n collection never looked so good...