Photoshop actions are a series of tasks that you play back on a single file or a batch of files that can include menu commands, palette options, tool actions, and so on. You can create Photoshop action that changes the size of an image, applies a filter to the image for a particular effect, and then saves the file in the desired format.
Here a series of Photoshop actions I use for photography manipulation. In recent time these have become overused with iPhone apps like Instagram.
Either way, enjoy these freebies.