| Extension |
File Type |
File Description |
| .i | Developer | INTERCAL Source File |
| .i00 | Disk | DVD Shrink Part 1 File |
| .i01 | Disk | DVD Shrink Part 2 File |
| .i02 | Disk | DVD Shrink Part 3 File |
| .i5z | Data | IUCLID 5 Import/Export File |
| .iam | Image | Inventor Assembly File |
| .ib | Data | InterBase Database |
| .ibp | Disk | IsoBuster Managed Image Information File |
| .ibq | Disk | IsoBuster Managed Image File |
| .ibt | Game | Texture and Model File |
| .ic1 | Image | Low Resolution Imagic Graphic |
| .ic2 | Image | Medium Resolution Imagic Graphic |
| .ic3 | Image | High Resolution Imagic Graphic |
| .ica | Image | Image Object Content Architecture (IOCA) File (Most common) |
| .icb | Image | Targa ICB Bitmap Image |
| .icc | Settings | ICC Profile |
| .icd | Settings | Installable Client Driver File (Most common) |
| .ice | Compressed | ICE File Archive |
| .icl | System | Windows Icon Library File |
| .icm | Settings | Image Color Matching Profile |
| .icn | Raster Image | Windows Icon File |
| .icns | System | Mac OS X Icon Resource File |
| .ico | System | Icon File |
| .icon | Raster Image | Icon Image File |
| .ics | Data | iCalendar File (Most common) |
| .id | Misc | Lotus Notes User ID File |
| .idb | Developer | Visual Studio Intermediate Debug File |
| .idc | Web | Internet Database Connector File |
| .idf | Settings | MIDI Instrument Definition File |
| .idlk | Misc | InDesign Lock File |
| .idw | Image | Inventor Drawing |
| .idx | System | Index File (Most common) |
| .idx0 | Game | Runescape Cache Index File |
| .idx255 | Game | Runescape Cache File |
| .iff | Audio | Interchange File Format (Most common) |
| .ifo | Video | DVD-Video Disc Information File |
| .igc | Data | Anime List Builder Input File |
| .iges | Image | IGES File |
| .igs | Image | IGES Drawing File |
| .ihw | Settings | N-HEH Timeline Workspace |
| .ihx | Data | IN-HEH Timeline Database |
| .iif | Data | Intuit Interchange Format File |
| .iil | Text | CleanSweep Installation Log |
| .iim | Executable | iMacro Macro File |
| .iip | Settings | ThinAnywhere Configuration File |
| .iix | Misc | Translation Memory Index File |
| .ilbm | Image | Deluxe Paint Graphic |
| .ildoc | Page Layout | QuickSilver Document |
| .ima | Disk | Disk Image |
| .image | Disk | Apple Disk Image |
| .imapmbox | Text | IMAP Mailbox |
| .img | Disk | Macintosh Disk Image (Most common) |
| .imj | Raster Image | JFIF Bitmap Image |
| .iml | Misc | ACT! Internet Mail Message (Most common) |
| .imovieproj | Video | iMovie Project File |
| .imovieproject | Video | iMovie Project |
| .imy | Misc | iMelody Ringtone File |
| .in | Misc | Spyware File |
| .inc | Developer | Include File |
| .ind | Page Layout | InDesign Document (Most common) |
| .indd | Page Layout | Adobe InDesign File |
| .indt | Page Layout | InDesign Template |
| .inetloc | Misc | Internet Location |
| .inf | Settings | Setup File or Installer Script |
| .info | Raster Image | ZoomBrowser Image Index File |
| .ing | Misc | MasterCook Ingredients File |
| .ini | Settings | Windows Initialization File (Most common) |
| .ink | Raster Image | Pantone Reference File (Most common) |
| .inm | Misc | FaxMaster Document |
| .inp | Data | ABAQUS Input File |
| .ins | Data | Inspiration File (Most common) |
| .int | Raster Image | SGI Integer Image |
| .inx | Page Layout | InDesign Interchange File (Most common) |
| .ion | System | 4DOS File Description |
| .ip | Data | IconPackager Theme File |
| .ipa | Executable | iPhone or iPod Touch Application |
| .ipd | Backup | BlackBerry Backup File |
| .ipf | Executable | SMS Installer Script (Most common) |
| .ipg | Compressed | iPod Game File |
| .ipk | Compressed | Itsy Package |
| .ips | Game | Internal Patching System Patch File |
| .ipsw | Misc | iPod and iPhone Software Update File |
| .ipt | Image | Inventor Part File |
| .iqy | Web | Internet Query |
| .irock | Data | intelliRock Sensor Data File |
| .irr | Data | Brewer Lamp File |
| .irx | Data | Brewer Irradiation File |
| .isc | Developer | Xilinx Device Configuration File |
| .isf | Data | Inspiration Flowchart Document |
| .ish | Compressed | ISH Compressed Archive |
| .isn | Misc | Installer Source Files |
| .iso | Disk | Disc Image File |
| .isp | Settings | IIS Internet Service Provider Settings |
| .isr | Game | GoMoku Game File |
| .iss | Developer | InstallShield Silent Response |
| .isu | Executable | InstallShield Uninstaller Script |
| .isz | Disk | Zipped ISO Disk Image |
| .it | Audio | Impulse Tracker Module |
| .itc | Misc | iTunes Cover Flow Data File |
| .itdb | Data | iTunes Database File |
| .ithmb | Image | iPod Photo Thumbnails |
| .iti | Audio | Impulse Tracker Instrument |
| .itl | Data | iTunes Library File |
| .itm | Data | iThink Model File |
| .itn | Data | TomTom Navigator Itinerary File |
| .its | System | Internet Document Set (Most common) |
| .itw | Data | InTouch With Database File |
| .itx | Data | ITX Form Template |
| .iv2i | Backup | Norton Ghost Incremental Virtual Volume Image |
| .iva | Misc | Dementia.4207 Virus File |
| .ivf | Video | Indeo Video Format File |
| .ivr | Image | Image World (Most common) |
| .ivs | Video | Internet Streaming Video |
| .ivt | Data | Beyond 20/20 Table (Most common) |
| .iwd | Game | Call of Duty Game Data File |
| .iws | Misc | InstallWatch Scan File (Most common) |
| .ixa | Disk | Ulead Disc Image format |
| .izz | Video | Isadora Media Control Project |
| .izzy | Video | Isadora Project |
