The best way to use your action over a widespread area is to create a droplet that you can just drag files into!
Go back and learn how to record actions
One small problem, Photoshop will throw up a save dialogue box for your images if you're opening and resizing them (not previously saved by Photoshop). The only solution I can think of us to do a save as and play with that or this:
The dumbell to the rescue.
(note: mouse is used as a wedge 
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