Tumblr, a microblogging platform, allows you to add pictures to your text posts on the blog. These photos are not centred on the screen when you insert them, so you need to add HTML code to centre the images in the post. You do not need to know any additional HTML code to centre your Tumblr images.
Load a Web browser, and go to Tumblr.com. Log in to your Tumblr blog.
Click the image icon, displayed as a small picture of a tree. Upload the image that you want to post and centre.
Click the "HTML" button on the far right side of the visual editor. Surround the image code, which usually starts with "<img," with "<div align="center">" and "<;/div>." Finish the rest of your post, and click "Create Post."