Mark Zukerburg decided not use Dislike button for Facebook. But, a lot of thanks to extension makers who created an extension, by which we can dislike an image or status which we hate.
1. Just install the the extension for Facebook dislike button
If You are using GOOGLE CHROME then click on it DOWNLOAD
If You are using FIREFOX then click on it DOWNLOAD
Now, after Installation, dislike will start to appear on Facebook.