Igni-chan (イグニーちゃん) is the official mascot of IRIX Network, and a personification not of IRIX, or SGI, but of the IRIX Network and all of its constituent projects. It's not to be confused with the logos, which are part of the official branding.
Igni-chan was designed and patterned after Project Kitsune's "Ignis the Fox" logo. As Project Kitsune funds, supports and manages IRIX Network. The concept is thanks to an artist going by Kyo/Kyokuusei, and was directed by Raion.
IRIX Network's spiritual predecessor, Nekochan.net, had a Neko girl mascot drawn by Nekonoko. A significant portion of the SGI community also intersects with Japanese anime and manga communities, and Raion wished to continue this tradition.
In canon, Igni is a foxgirl who owns a SGI Tezro named Kumokyu (Cloud Nine). She can summon SGI cubes in her right hand, and dresses mostly in traditional clothing in public.
Original drawings of Igni-chan are done by Kyokuseii They are copyright of Kyokuseii and IRIX Network jointly. Any person may draw, or reuse, assets containing Igni-chan as long as credit is provided to both Kyokuseii and IRIX Network for the original creation.