CoolPic is a cool browser extension which will help you to give a funny look for your Facebook, Picasa and Flickr images.It allows you to add hats, mustaches and props to your photos . It works with IE, Firefox and Chrome only.
After you install coolpic just open the site (Facebook, Picasa and Flickr ), click the coolpic Button and your image will be shown on the editor, The manipulations are so easy, after finishing it just allow the coolpic to upload the images for you. (Water marks will be there on the image. The original image will not get affected by the editing.
You can read more and use it from here
See the option available below
So if you like to add some funny elements to your photos, you can try CoolPic