Maybe this has been covered, but I can't figure it out.

In Photoshop/ImageReady 7:

I need to run a batch automation on a directory of images, whcich will
add an effect (stroke/drop), then SAVE FOR WEB, overwriting the source
image with the same name.

How do I set this up? I've got the action set, but I cannot figure
out how to save for web over the original file without PROMPTS.

Can it be done? I'm no PS slouch and I've fought with this for hours

If you know how, please respond!