To change resolutions manually go to game client and open LauncherOption.if file with notepad.

Copy paste folowing:

DevModeIndex: 0-6 ( choose what number acording to resolution you wish )

//0: 800x600 (4:3)

//1: 1024x768 (4:3)

//2: 1152x900 (4:3)

//3: 1280x720 (16:9)

//4: 1280x800 (16:9)

//5: 1280x920 

//6: 1440x900 (16:10)

WindowMode:1 On, or 0 Off