Is this for some kind of sensing pics ?
..trying to figure out why having lat & longtitude is important in a photo.
Presumably, some new digital cameras, and cell phones with cameras, have built-in GPS units that automatically record the location the picture was taken in the EXIF metadata, in addition, there are EXIF editors where you can enter the location manually.
The reason? One popular use is to link them to Google Earth, so that people can see pictures of places all over the globe. It also beats trying to remember just where you took that 10 year old photo.
JimN