automated action using the batch button

Record the action first. Just open one image, start recording, do whatever you need to do, stop recording.

Then open the Batch dialog, choose source, and point it to your action. The simplest way to do it is through Bridge. Select the images there and Tools > Photoshop > Batch.

One thing you need to pay particular attention to is Destination. What you absolutely want to avoid is to overwrite your originals, which can easily happen. There are two ways to avoid this:

• include a destination in your action. Then it's important to Save As to that destination, and end the action with close without saving. If you do it this way, you set destination to "none" in the Batch dialog. This is pretty idiot-proof (I use it myself...)
• the other way is to set destination folder in the Batch dialog, in which case there is no Save step in the action - or if there is, uncheck it.

There is an "override open and save steps"-option in the Batch dialog, but it's confusing and best avoided. It's easy to make mistakes here.