I was using PhotoShop a long time before I read about
Actions. If you need to resize a whole bunch of pictures, or de-interlace a whole bunch of pictures, add a filter, apply a saved curve, or whatever, put a copy* of all those pictures into a special folder and create an action. Then let PhotoShop apply that action to your folder. (I always keep a folder of the originals and make a copy w/ the effect I need.)
Ready? Go to
Window > Actions to open teh Actions pallette if it isn't open.
Now click to the twirl-down menu at right and pick
New Action:

Name your action & click
Record:

Do everything you wish to automate. In this example I resized and then used a filter. When you are done, press stop at the bottom of the Actions Pallette.

Now you will apply this action to your folder. Go to
File > Automate > Batch as shown below:

In the Batch window, be sure to pick your action, pick your folder, and choose the
Save & Close option. See below:
