James is looking for an app that will help him to edit the metadata that is in his still images. He wants one that will allow him to put in a description and then search for keywords. Leo says that all photos have extended information tags, or "EXIF" data. There's also a standard called IPTC that does titles and descriptions. So it can be done. Most photo library programs, like Adobe Lightroom will do it. There's a free one called Photo Me.
Another option is Fast RAW Viewer. He can try it before buying.