How To add Thumbnail in search result?

i search any kind of recipe,sample "chicken recipe" at google,i see some sites have thumbnail image and star on google search result...how to do this?any trick?
i use wordpress,any plugins to do this?for the image thumbnail

You should be search on YouTube; here you can found many video and information. Enter search keyword In YouTube "Adding Thumbnail Images to Your Word press Blog". I thinks this information really helpful for you.