1. https://24.media.tumblr.com/e50d33d6d1e3979ee53d7a34d1ff887d/tumblr_msfre5tEl71q
m1z0oo3_250.gif
STEP ONE:
Open up tumblr.com/customize and open "EDIT HTML"
STEP TWO:
copy/paste this anywhere AFTER "<style type="text/css">"
#popup
{right:0px; bottom:-3px; position: fixed; }
STEP TWO:
copy/paste this AFTER "<body>" but BEFORE "</body>"
<a href="http://popupgif.tumblr.com"><div id="popup"><img
src="http://i41.tinypic.com/314ayqx.gif" height="157px"></div></a>