Add an image to a hashtag You can add an image at the domain level of already defined hashtags if you have the admin role. Click Hashtags in the sidebar. Select the appropriate hashtag. Do one of the following: Locate the image in your file system, and then drag-and-drop the image onto the add an image icon (). Click the add an image icon (), select the image file, and click Open. To change the image, simply drag-and-drop a new image onto the old one, or click on the existing one and select a new image. When you view a message that contains a hashtag with an image, that image appears in the hashtag heading bar.