I am taking care of a WordPress blog, and when I had updated it, I accidentally deleted all uploaded images. Fortunately, he who owns that site has backup for them. Actually he had, but WordPress converts file case to lower case when users upload their files, so he had to rename them manually before upload them. So I made renaming software for him. This software is upgraded version. You can only rename but add prefix, suffix, digits, and keep original filename intact. Finally you can make them upper case, lower case or case no change.
So it looks like this.

This is a preview mode. See the "Preview filename" check box is checked.
When you click on the button "Rename", a preview dialog will appear (see below).

There is a "Rename" button here, but actucally it says OK. I changed it.
You can download Renamer from the following link from MyLivePage.
File Renaming Software for PC Windows.zip
The software will work on Windows 95 - XP.