In Text Posts
When composing text posts, you can upload images, including animated emoticons, directly to Tumblr from within the edit screen for the post. Place the text cursor where you want the emoticon to appear, click the “Upload Image” button, browse to the location of the emoticon on your hard drive and double-click the file. The emoticon will upload to Tumblr and appear in your post. If you want, you can also insert images that are already hosted somewhere on the Internet, but you’ll need to click the “HTML” button and insert the raw HTML code for the image yourself (see Resources).
In Other Post Types
When composing posts that aren’t of the text type, you can only add emoticons that have already been uploaded to the Internet. Click the “Insert/Edit Image” button, paste the URL to the emoticon in the “Image URL” field and then click “Insert.” If the emoticon is on your hard drive, you’ll first need to upload it to a hosting service such as TinyPic, Photobucket, ImageShack or Imgur (see Resources).
