One of my favorite photo manipulation effects is High Definition Range, better known as HDR. The colors this effect brings out along with the depth created through unusual lighting tricks adds an almost magical look to any subject. HDR photos work for unique product photos, landscapes, waterscapes, stills, and occasionally portraits.
However, most photographers lock down their HDR photos with a firm copyright, and with good reason. Anyone can create an HDR photo, but not everyone can create one that is truly stunning. Sometimes, though, an artist will provide a few creative commons HDR photographs simply as a way to get noticed. If people can share in the right way (i.e. by attributing the work to the artist with a link to the source), the more willing photographers are to provide photos for us to use.