Social networking services have become part of our quotidian existence nowadays. To render the Internet more entertaining and enjoyable, an increasing number of Internet artists have created many humorous illustrations in recent years. These illustrations not only convey their creators' sense of humor in an intelligible fashion, but also gradually replace complicated and lengthy texts. Applying the evaluation grid method (EGM) from the Miryoku engineering, this study seeks to investigate the attractiveness factors behind humorous illustrations. According to the evaluation grid produced via in-depth interviews, this study identified that these attractiveness factors include content, style, text, and color, which may serve as a practical reference for the creation of online graphic texts.