
Flickr is a wonderful example of open source software and so many people have used its code to create third party sites and tools. I found a neat one called PicMarkr which allows you to upload your photos directly from Flickr (or another photo hosting site) and apply a watermark to your photographs. PicMarkr markets itself as a tool that allows you to feel safe about putting your photos online because the watermark serves as a way to protect your ownership of your images.
I used it to add a watermark to one of the photographs I took this summer at a cottage near Haliburton. It was a beautiful day!