Geotagalog automatically geotags photos to tracklogs using the timestamps in your photos and in your tracklog. For the most accurate positioning, you will need to make sure your camera's time zone and any slight error are set correctly in Geotagalog before importing. As you change the camera time zone and error settings, Geotagalog will show a live preview of each photo's location so you check the results.
If any photos cannot be geolocated well with the provided track data, they may show up in light yellow on the map or disappear from the map completely. When this happens, Geotagalog will enable the "Don't geotag when unsure of location" checkbox. You may use this to decide what to do with these photos.