Flickr has a new Easter Egg (or would that be a Christmas egg?) as part of its programming. If you place a note on a photo with the phrase "ho ho ho hat", a Santa hat will be added to the image. Likewise, if you add a note with "ho ho ho beard", a Santa beard will appear. The image itself is not altered. An image overlay is incorporated into the note. You can size it and move it to fit.
For example, look at the image of Laura and me to the right. It appears normal here, but if you click on it to go to the Flickr photo page, you’ll see the additions. Scarily enough, the overlays look natural on me!