Well when you find out how, be sure to write a Tutorial and share it, because the Macro function of Photoshop is a mystery to me
Ok, do this:
1. On a dummy image, create an Action with the steps you want to apply to a bunch of images. (in this case, i used I-KP's glow suggestion in the other thread then a Create Layer, Merge Visible, and Save)
2. Open Automate (in file) then Batch...
3. Select the Action you just saved, Folder source with the folder you want to apply it to then check off the bottom 3 checkboxes below that.
4. Destination = Save and Close with Override Action "Save As" commands checked
Click ok and it will start working. The Save action is overriden so that it saves over the original files!