Creating the Action: To do this first open the Actions Palette. Window|Actions
Then at the bottom of the palette click on the icon next to the Trash Can (Create New Action).
Name your action, Set: Default Actions.atn, choose a function key (if you want to use that feature) and colorize it if you want.
Then press RECORD and note how at the bottom of the Actions Palette the Red Circle button is depressed and anything that you do now will be recorded until you press the stop button.
Go through and do all the actions you want to do (crop, resize, save, etc) then press stop.
To apply the action to an image, open the image and then press your key command that you set. If you did not set a key command then simply click on the name of the action you made and press the play button at the bottom of the Actions palette.
The next part discusses how to apply your action or any other action to a larger quantity of images.
Batch Processing Goto: FILE|AUTOMATE|BATCH Set: Default Actions.atn Action: The action you made or any other action Source: Folder Choose the folder where all the images are Destination: Another folder, or choose none to keep them all in the same folder Errors: Stop for Errors
Then press ok and watch Photoshop apply the action of your choice to all your images in the specified folder.