Dreamwidth moods are the words like "angry," "sad," "happy" and so on you see at the bottom of your text edit box and (generally) below your entries, denoting the mood associated with the post. A mood theme is a set of static or animated images (up to 100 by 100 pixels) to visually differentiate these moods. As far as I can tell there's very little documentation of Dreamwidth mood themes, especially how to customize them, so I thought I'd give a little rundown of how to set mood themes in Dreamwidth, from the basics of switching to a different public mood theme (available to all account levels) to creating and editing custom moods (paid account and above). As a bonus I'll also provide my own mood theme that you can install easily from the admin console.