The following code can be cut and pasted into a Windows batch file for generating png thumbnails of all the svg files in a directory
and its subdirectories. A thumbnail is not generated if the svg file has not changed (after the previous generation).

In order to use this:
1. Create a new directory and a subdirectory;
2. Save a few svg files in them;
3. Cut & paste the code into a text file (use "notepad"), set inkscape.exe path according to the actual location, then save the
file as (e.g.) "generate.bat";
4. Create a small text file containing only the letter "F" and a carriage return, save it as "f.txt" in the same directory;
5. Double click on "generate.bat" in Explorer to launch the program;
6. Check that the result is as expected.

Note: there is some WXP console feedback, if you do not need it just erase the lines "echo/|set /p =." and "echo %%i".



HTH