ICA Citrix file

ICB Targa bitmap

ICM Image Color Matching profile file

ICO Windows Icon

IDD MIDI Instrument Definition

IDQ Internet Data Query file

IFF Amiga ILBM

IGF Inset Systems metafile

IIF QuickBooks for Windows interchange file

IMA WinImage file

IMG GEM image

INC Assembler language or Active Server include file

INF Information file

INI Initialization file

INP Oracle source code for form, version 3.0 and earlier

INS InstallShield install script

INS X-Internet sign-up file

ISO Lists the files on a CD-ROM; based on the ISO 9660 CD-ROM file system standard

ISP X-Internet sign-up file

ISU InstallShield uninstall script

IT Impulse Tracker music module (MOD) file

IW Idlewild screensaver