How to batch rename file names in Photoshop?

Here are the steps:

1. First launch Adobe Photoshop if you haven't already done so.
2. Then press Shift+Ctrl+O to open the File Browser.
3. Next navigate to the folder where your images are stored.
4. Select your desired photos (Ctrl+A to select all, Ctrl+Click to select individual ones and Ctrl+Shift+Click to select multiple images next to each other).
5. Right click anywhere within the selection to bring the pop up window and click on the "Batch rename" menu.
6. Choose your destination folder (it's better to copy to another folder so that your original images are left intact).
7. Choose how to rename your files (see my note below).
8. Click on Rename and that's it.

In my example, I wanted to append the letter "s" to all filenames so that they become as follows:

Orginal file : aligator-wide-open-mouth.JPG
Renamed file : aligator-wide-open-mouth-s.JPG (observe the -s which gets added to the name)

So for the options, I've chosen Current Filename (just the name, not the extension) and then I've entered -s as Text which gets me my desired output file name. You can however choose from a number of options including date & time or sequence numbers, it's really up to you how you want to name your images.

PS : I'm using Photoshop CS3 on a Windows 7 machine, so the steps might be slightly different if you're using a different OS or version of PS.