Post To Tumblr is an extension for the Chrome Browser. It started off as a simple one-evening project to solve an annoyance with Tumblr, before long however it had thousands of users. At the time of writing it currently has 32,000+ users.
You can download the extension here: https://chrome.google.com/webstore/detail/post-to-tumblr/dbpicbbcpanckagpdjflgojlknomoiah?hl=en
Over the years it has gone through many different versions and rewrites, checkout the following posts for more info: [catlist id=26 numberposts=500]