Recs.
Updated
It is a lightweight, folder based photo viewer for Mac, having simplicity as its core feature. It has a free version, and a paid $5 version with more features.
Specs
Pros
Pro It handles all picture file formats, and most video and audio formats too
It will handle both the standard formats, like png, jpg, bmp, gif, tiff and camera, and the RAW formats like crw, cr2, dng, eip, erf, nef, nrw, obm, orf, pef, raw. It can also handle many video formats: mp4, m4v, m4u, m4a, mkv, mov, and audio formats as well: opus, weba, webm, ogg, ogm, oga, wav, mp3, flac, m4v, acc.
Pro It handles all picture file formats, but also most video and audio formats
It will handle both the standard formats, like png, jpg, bmp, gif, tiff and camera, and the RAW formats like crw, cr2, dng, eip, erf, nef, nrw, obm, orf, pef, raw. It can also handle many video formats: mp4, m4v, m4u, m4a, mkv, mov, and audio formats as well: opus, weba, webm, ogg, ogm, oga, wav, mp3, flac, m4v, acc.