A droplet applies an action to one or more images, or a folder of images, that you drag onto the Droplet icon. You can save a droplet on the desktop or to another location on disk.
Actions are the basis for creating droplets—you must create the desired action in the Actions palette prior to creating a droplet. (See Recording actions.)
When creating droplets for both Windows and Mac OS, keep the following compatibility issues in mind:
After moving a droplet created in Windows to Mac OS, you must drag the droplet onto the Photoshop icon on your desktop. Photoshop updates the droplet for use in Mac OS.
When creating a droplet in Mac OS, use the .exe extension to make droplets compatible with both Windows and Mac OS.
References to file names are not supported between operating systems. If an action step references a file or folder name (such as an Open command, Save As command, or adjustment command that loads its settings from a file), execution pauses and the user is prompted for a file name.