Just as a matter of interest Brian, how would you define a snapshot?
The definition I have been using is one I found in a photographic magazine about 30 or so years ago.
“A snapshot is a picture made without much thought or application of technique.”
Another interpretation might be, a picture made to capture the moment, or document a scene, but without paying any attention to trying to get a good result.
You might also think of this as “what does a photographer or photo enthusiast do while making a picture that a neophyte does not do”.
Here’s something I witnessed at a friend’s house while we were all sitting around in the living room. His mother saw something she wanted to take a picture of, grabbed up the camera, but backwards, put her eye up to the flash instead of the viewfinder, and pressed the shutter. It was maybe an hour before she could see properly again.
Now that’s an extreme case of not thinking, in this case to check first that the camera was pointing the right way.
Probably more important is how I might interpret that definition:
Let’s first look at what is implied by “without much thought” while making a picture. To me this would probably mean not much thought with regard to composition, vantage point, framing, deciding whether a vertical or horizontal orientation is most appropriate, trying to catch the decisive moment, waiting for a good expression (when that is appropriate), trying to elicit a good expression (when appropriate), paying attention to background objects that might align in an unfortunate way with the subject, trying to get the horizon level, exercising creative expression.
For technique that might include not putting much or any effort into getting the picture in focus, where to place the point of focus, considering the necessary depth of field, evaluating whether some adjustment was required to get a good exposure, ensuring you won’t have image data go off-scale (blown out highlights), paying attention to lighting conditions, lighting quality, lighting direction, paying attention to the correct white balance, noticing if the current shutter speed will result in a blurry picture (if you want a sharp one). And if you want to consider overall image quality then using a tripod is pretty standard.
A couple of other useful definitions.
Pre-visuslizing the result. You have some idea of what you are trying to achieve and use your photographic experience to work towards that objective. You look at a scene and in your minds eye you see how you want it to look, not how it really looks.
“Seeing photographically” means you know by experience the difference between what you see and how the photographic process will actually render it (based on the current deficiencies in the processes), and take steps to try to overcome the weak points and make full use of the strong points.
Just sayin’. 
