Windows orders files by name alphabetically as if 1 was a character not a number if that makes sense.
So 1, 10, 100, all come before 2, 20, 200, and before 3, 30, 300.
So if the filenames are the same length will padded zeros, then 001, 002, 003, 004 will be in the right order.
It doesnt actually read the file names, it just reads it in as Windows passes the file information.