User blog comment:Omega natsu2/Episode 201: Delivery, Review./@comment-4489126-20140927025825/@comment-3424593-20140927033714

Yup I was right. If you use Chrome's Developer Tools in this page you'll see that each image's name is in order according to the zodiac. For example, Seirei_01 is Aries, Seirei_02 is Taurus, Seirei_03 is Gemini, Seirei_04 is Cancer, Seirei_05 is Leo, etc.