I have already written about reverse image search and what it really is. Just to refresh your memory, it is an image search engine where you search an image and you get results related to that image. The results tell you more about the picture you just searched and related pictures info.
If you find a picture on your computer or in a photo album, you can use reverse image search to try and determine where it was taken. Simply go to images.google.com or any other search engine that can reverse image search.
From the results, you can determine where the picture was taken. But this method is very limited because it can only determine the locations of pictures with popular land marks. e.g. buildings, rivers, mountains e.t.c.
This method is used to determine the location of physical photographs and old digital photos. Modern digital cameras and smartphone cameras embed co-ordinates in them and it’s easier to find their location even if they were taken in a room.