Credit:
A simple yet effective service called CMP.ly makes it easy to disclose such connections (or lack thereof). It consists of 5 simple links (http://cmp.ly/0, http://cmp.ly/1 and so forth), which you can use simply by attaching text such as DISCLOSURE OF MATERIAL CONNECTION: http://cmp.ly/0 at the bottom of your media posts.
It's quick and easy, and you can even do it on microblogging services such as Twitter. You've got 5 different disclosures to choose from, and a sixth one - a custom disclosure - is coming soon.