Successfully complete Arcade mode the indicated number of times to unlock the cover art of the corresponding King Of Fighters series game and other illustrations as well.

Illustration	How to unlock
King Of Fighters '94 Illustration	One time.
King Of Fighters '95 Illustration	One time.
King Of Fighters '96 Illustration	Two times.
King Of Fighters '97 Illustration	Three times.
King Of Fighters '98 Illustration	Four times.
King Of Fighters '99 Illustration	Five times.
King Of Fighters 2000 Illustration	Seven times.
King Of Fighters 2001 Illustration	Eight times.
King Of Fighters 2002 Illustration	Nine times.
King Of Fighters 2003 Illustration	Thirteen times.
King Of Fighters XI Illustration	Thirteen times.
King Of Fighters XII Illustration	Fourteen times.
Special Illustration 1	Nine times.
Special Illustration 2	Fifteen times.