It's not much of a ranking signal, but adding image descriptions in the metadata (like an alt tag) may help with visual search, and geotagging may be a slight signal to help with local search. To edit, in Windows you can just right click an image, select properties, then the details tab. Double clicking on an entry will allow you to edit a field.
But IMO your time is better spent working on on-page optimization, internal linking and external backlink building.