The Locate tool appears when a multipoint or control point item is selected in the Import Viewer. Select the multipoint or control point in the grid then press Locate… to open the photo(s) on which that point projects. A warning appears if the point does not project onto any photos. The Choose Number of Photos to Open dialog opens if the point appears on multiple photos.
If the imported point (i.e. a geo-control or geo-transform imported point) is calculated to lie significantly off a best fit plane of points in the model, it could be that the imported elevation value is off - the Locate Elevation Mismatch Dialog appears.