I recently decided that I wanted to go through some photo albums on my Mac and rename the individual pictures form IMG_xxxx.jpg to something a little more searchable and descriptive. I mean, who wants to look at this?
Here's how I did it, and it is actually really easy!
1. Open up "Automator". It's in your Applications folder.
2. On the screen that pops up asking what you want to do, just select Workflow.
3. On the left side of the main screen, select "Files and Folders", then in the next panel over, drag "Get Specified Finder Items" to the far-right panel. Once you do that, scroll down in the middle panel and drag "Rename Finder Items" over as well.
4. It will ask you about making a copy of your files since you will be renaming them. You can if you want, but I skipped it.
5. You have some options in the bottom box in the far-right panel. This mostly affects how you want the files renamed. For example, I wanted the files to be renamed with a sequential number at the end of each one that followed a space after the name (you will see what I mean when you see the end result). Play around with these options to get it to act just how you want it.
6. In the top box of the right-panel, drag your files into it that you want to change. Once you do that and choose your options below, hot the "Run" button at the top-right.
7. It will take a few seconds, and when it's done, you will have a folder of neatly named files. Yay!