From Yarra Valley Software:
Action 1: Add Metadata to Image Files: This Automator Action allows you to add metadata like, copyright, artist, info and gps information to image files.
Action 2: Apply Watermark: This Automator Action allows you to use an image as a watermark that you can overlay over other images. If the watermark image has a alpha channel (transparency) the blending will be a combination of the alpha channel plus the opacity setting in the script.
Action 3: Draw Text on Image: This Automator Action allows you to draw text onto your image files. You might want to add a copyright notice, or add some text like the names of people in the picture or where and when it was taken. The action provides options to specify the font size, the text colour, the text background colour or whether the text background is transparent.