Batch processing allows running a series of programs or jobs on a computer without manual intervention. To batch process files using an action in Photoshop or Bridge, select the action, files, and processing options. You can batch process files in a folder and its subfolders by choosing "Folder" as the source, setting the destination to "Save And Close," and overriding the action's "Save As" commands so files are saved in their original folders with automatically generated names.