The purpose of creating a droplet in Lightroom is to run Photoshop actions after you have exported your image out of Lightroom. This is very handy if you want to create any custom actions, like watermarking your images if you do not like Lightroom’s watermark or adding a frame around your image. In this article I will show you how to create a small 4 pixel frame around your image.
First we need to write the action in Photoshop, so open an image that is correctly sized for what you want to do, in this case I opened an image that is resized to 1020 pixels x 680 pixels (the height was the default size). The reason I selected 1020 pixels is because I am going to add another 4 pixels for my frame bringing the total width to 1024 pixels. See image below: