This extension lets you post photos, videos, mp3s, quotes or links to your Tumblr account by right clicking on the stuff that you want to post and then click on the associated "Post to my tumblelog" menu item in context menu that pops up. By default content will automatically get posted to the tumblelog you've selected. However, if you want to attach the optional values for each content type, like
![Tumblr Post :: Add-ons for Firefox](https://cdn-ak-scissors.b.st-hatena.com/image/square/1052f613ed7db3f2e4034cdd0c2445cb5f5e5e59/height=288;version=1;width=512/https%3A%2F%2Faddons-amo.cdn.mozilla.net%2Fstatic%2Fb4ed07ea73fd9b86f6ace81025f9c6eb.png)