This photo was taken on Arizona Highway 87. To get this result, I started by increasing the saturation to 15 (Edit, Colors, Saturation) and the contrast to 100 (Edit, Exposure, Contrast). Next, I went to the Create menu and applied the "Focal Soften" filter (Create, Effects, Focal Soften), adjusting blur to 30 percent, focal size to 75 percent, edge hardness to 25 percent, and fade to 20 percent. I also added the "Vignette" filter with default settings and added the "Rounded Edges" frame.
Picnik is an excellent choice if you don't already have a go-to photo-editing program such as Adobe Photoshop or GIMP. Picnik's premium features are interesting, but they're not necessarily worth $25 a year--unless you happen to be doing a lot of actual photo editing. The premium features include various touch-up options, such as dodging and burning on photos, using a clone stamp, and airbrushing. If you just want to add filters and the like, you'll be fine with the free version.