I have searched the net for months looking for a link for tumblr for Blogger and finding nothing decided to modify another link to suit the purpose. Feel free to add to your blog (This only works with Blogger)
Save the below image to photobucket or similar.
Copy the code below and paste it inside the content box.
Replace “USERNAME” with your tumblr username.
Replace 'TUMBLR DIRECT LINK HERE' with the direct link from your photo host.
<a href="http://USERNAME.tumblr.com/"><img src="TUMBLR IMAGE DIRECT LINK HERE" width="60" height="60" alt="Follow Me on Tumblr" /></a>