It uses the EXIF data, so it would use the location data in the EXIF.
> So this would not work with photos taken with a DSLR without a GPS module/attachment.
Depends. You can also retroactively edit the EXIF data to reflect a location. It should work on those kinds of pictures, even though the original camera didn't have a GPS.
> So this would not work with photos taken with a DSLR without a GPS module/attachment.
Depends. You can also retroactively edit the EXIF data to reflect a location. It should work on those kinds of pictures, even though the original camera didn't have a GPS.