answer:First, you need to build a Flickr badge. To do so go here, select what type of badge you want and customize your badge if you want to. When you are done building, Flickr will give you some code. Copy this code. Now paste this code onto the “Desciption” area on the “Customize” section of tumblr. Does your theme have a sidebar? and the thumbnails might be positioned differently depending on what theme you are using. What theme are you using ?