OptiFine on Twitter: "Website is back up, and broken capes should be fixed. There is also a new "Banners" tab where you can view the most popular OptiFine banner cape designs currently.
Official AYS Optifine banner Capes | Hypixel - Minecraft Server and Maps
How To: CROWN OPTIFINE CAPE! (Optifine Cape Designs) - YouTube
5 Black & White Optifine Cape Designs! (Best Minecraft Cape Designs) - YouTube