Time for some lessons in old fashioned pre-windows computing. Way back in the day, before Windows, there was such a thing as DOS (MS-DOS, PC-DOS).
You don’t say how you want them divided, so I’m going to describe doing it alphabetically. You can adjust it you need to.
1. First, in Windows, type in COMMAND or CMD. That will put you in DOS command mode.
2. Decide where you’re going to put the pictures. For this example, I’m going to say the c:\pictures directory. You can put yours anywhere.
3. Type c:\ <return> which will put you at the top level of your disk
4. type MKDIR Pictures (you are making a new directory for pictures)
5.type CD Pictures – changed directory to the Pictures directory.
6. You are going to make 26 subdirectories (folders) one for each letter of the alphabet:
MKDIR A
MKDIR B
MKDIR C
and so on
These directories will be the target for when you do your copying.
7. Figure out where the pictures currently are. For our purposes, let’s say there are in C:\PICS\OLDPICS. (Obviously they will be different for you.
8. Go there. CD C:\PICS\OLDPICS
9. Now for the fun. You are going to do this 26 times, once for each letter of the alphabet
COPY A* c:\Pictures\A
which means -> copy all pictures in the old folder that begin with ‘A’ to the new subfolder A that we just created.
Now do it for all the pictures that start with B
COPY B* c:\Pictures\B
and so on.
There are probably other ways, but this is easy and foolproof.