To my mind there is a vast difference between a photograph and a snapshot.
A photograph is made, the photographer has a vision for the image in mind and sets about creating it. Waiting for the right light or weather conditions and often visiting the scene several times to get it just right.
A snapshot on the other hand is taken as the opportunity arises, often with minimal thought. It is what we do on holiday, when out with family, it aids us in remembering those moments long past.
Having said that, many snapshots are perfect, just like the postcard, whilst some photographs, despite the time and effort, look like a hurried snapshot.
I take mainly snapshots, but occasionally, I get a beautiful photograph.