@ Kernelpanic - thanks for reply. Just to try to clarify a bit better...
In the very old "DOS days" - I wrote a simple BASIC program that printed very basic file directory information to very small "cards" which were about twice the size of standard business cards. The information included:-
Volume name (of 3.5 inch disk), serial number, file path ... AND a list of some 25 files in that path with information:-
Filename.ext date attributes clusters checksum etc AND the first 16 bytes of the file
The process was repeated for all files on all disks I had (no hard drive for me at the time). I ended up with hundreds of these "cards", which were of convenient physical size (actually fit inside sleeve of 3.5 inch disk), portable (ones being studied at the time fit in my shirt pocket) etc.
The most important aspect was "the first 16 bytes of each file" - a very crude "summary" of the file itself ("MZ" at the beginning indicated an .exe file for instance). So when file extensions were being changed at the time, and keeping in mind "virus attacks" at that time, I had a "primitive" means of "being aware" of "How When Where Why" (sort of) for each file. And using various colored "highlighter" pens and annotations - could group the cards into useful collections (all for use when away from a computer for long periods of time).
TODAY
Computer life is much more complicated and despite long file names being supported - more often than not - the filename.ext often gives "no clue" what a file is about. So a "simple summary" - and possibly the simplest approach is one format ( a "thumbnail" picture), whether it is some plain text, picture, etc. - would be a "modern" replacement for me from what I did in the past.
These "thumbnail pictures" would be portable (used independent from computer) - and although I may not hard copy print them out - would (on my grouping) still fit in my shirt pocket (eg for instance store pictures on a cheap mobile phone - so still 3.5" size and physically easy to work with. So, because of numerous problems with windows, for instance on many occasions Windows 10 put some downloads into a very heavily nested directory (many more than 6 levels down) and despite using Windows File Explorer Search (which for me seemed to ignore anything at more than 6 levels down for what I was searching for - the files (on occasions were effectively lost). The way around was to just use "DOS" and dump the entire C:\ drive to a text file and "wade through" all the 300,000 files + of windows, etc.
So now I try to automate (by using BASIC program) my methods - the large number of files warrant this - but still filenames (and extensions) may change ( for instance with a "virus attack" about a year ago, which as best I can tell came down (with "sheep's clothing" as a Video file) via YouTube (which was not actually launched by me). So I am back to "independently checking up on files" remote from a computer AND SO A SIMPLE SUMMARY AS A PICTURE IS HELPFUL FOR ME.
Windows 10 File Explorer PREVIEW PANE is probably good enough for me as you can see a "picture summary" for many file types. However, it requires access to a computer and also it is a pain to search through all possible directories (just look at the Windows folder itself for instance). I can write my own BASIC program to access just about any file, where ever it might be, but the "picture part for any file part" is the catch.
Hence why wanted to know how to program access Windows 10 PREVIEW PANE.
Hope the above clarifies my need a bit better.