I
| Ext. | Description | Used by |
|---|---|---|
| I | Preprocessor output file | Borland C Preprocessor |
| IAK | Internet Access Kit | OS/2 |
| IAM | Assembly file | Autodesk Inventor |
| IAX | Bitmap graphics (IBM Image Access eXecutive) | |
| IAX | data | InstallAnywhere.NET project |
| IBG | PDS graphic file | |
| IBM | Archive (Internal IBM only) | ARCHDOS |
| ICA | Bitmap graphics (Image Object Content Architecture) | |
| ICB | Bitmap graphics | |
| ICC | ICC configuration | |
| ICE | Archive | Cracked LHA (old LHA) |
| ICFE | IceFormula Equation Workspace | Penguin George |
| ICFM | IceFormula Math Workspace | Penguin George |
| ICM | ICC configuration | |
| ICN | ICON source code file | |
| ICO | Icon file | ICONEDIT.EXE; Microsoft Windows |
| ID | Disk identification file | |
| IDB | IDA database | IDA |
| IDB | VC++ Minimum Rebuild Dependency File | Visual C++ |
| IDC | IDA C language source | IDA |
| IDE | Borland C++ 4.x IDE project | BCW.EXE |
| IDF | MIDI instrument description | |
| IDS | IDA imported names format | IDA |
| IDW | Vector graphics | IntelliDraw |
| IDW | Drawing file | Autodesk Inventor |
| IDX | Index | many - FoxPro; also unrelated Quicken file format |
| IFD | Form | JetForm Design |
| IFF | Interchange Format File (IFF) | EA Software - Convert (C) Villena - Amiga |
| IFF | Sun TAAC Image File Format | SDSC Image Tool |
| IFP | Script | KnowledgeMan |
| IFS | Fractal image compressed file | Yuvpak |
| IFS | Iterated fractal system file | IFS Creation Kit, Apophysis |
| IFS | Installable file system | OS/2 |
| IGES | Initial Graphics Exchange Specification | |
| IGF | Inset Systems | GCGW |
| IGC | Flight tracks downloaded from GPS devices in the International Gliding Commission's prescribed format | |
| IHP | Watcom help file | whelp.exe |
| IHS | Inbound History | Bink/+ |
| IIW | Power Point Image Importer Wizard | |
| IL | hDC Designer Icon Lin dll format | |
| ILB | Data | Scream Tracker |
| ILG | data | LaTeX Index Generation log |
| ILK | Outline of program's format | Microsoft ILink incremental linker |
| IM | Auran Jet indexed mesh file | Trainz |
| IM8 | Sun raster graphics file | |
| IMA | Mirage vector graphics | EGO - Chart - Autumn |
| IMG | ADEX graphic file | |
| IMG | Disk Image | NC 5.0 |
| IMG | GEM bitmapped graphics file | Ventura |
| IMG | Image for Windows/Image for DOS Disk image | TeraByte, Inc. dba TeraByte Unlimited |
| IMG | Vivid IMG file | |
| IMI | image | Magellan Meridian map |
| IMI | image | Magellan eXplorist map |
| IMP | Spreadsheet | Lotus Improv |
| IMQ | Image presentation | ImageQ |
| IN | Design II for Windows INput file | |
| IN$ | Installation file | HP NewWave |
| IN3 | Input device driver | Harvard Graphics 3.0 |
| INB | Test script | Vermont HighTest |
| INC | Include file | several programming languages |
| IND | Data Index | dBASE IV |
| INDD | InDesign Document | Adobe InDesign |
| INF | Information text file (ASCII) | |
| INF | Install script | |
| INF | OS/2 hypertext help system file | VIEW.EXE |
| INF | Type 1 LaserJet font information file | soft font installers |
| INFO | GNU info reader (output from Texinfo) | info (Unix) |
| INFO | Icon Data (Amiga) | |
| INGR | Intergraph Raster File Format | |
| INI | Initialization file | |
| INK | Pantone reference fills file | CorelDRAW |
| INS | Data | WordPerfect |
| INS | Ensoniq Instrument File | Ensoniq |
| INS | Installation script | 1st Reader |
| INS | Instrument music file (Adlib) | |
| INT | Borland Interface Units | |
| INT | Program saved in Internal (semi-compiled) format | Signature |
| INT | Source of Borland interface module | |
| INX | Index | Foxbase |
| IO | Archive | CPIO |
| IOB | 3d graphics database in TDDD format | Imagine |
| IOC | Organizational chart | Instant ORGcharting! |
| ION | 4DOS descript.ion file (file descriptions) | 4DOS, VC, NDN, Total Commander, XnView |
| IP | Immortal Player file | Immortal Player |
| IPC | Intellitec Program Configuration - used to configure vehicle electronics | Intellitec |
| IPF | Interchangeable Preservation Format | SoftPres |
| IPG | iPod game file | iTunes and iPod |
| IPH | Hi-Res Image | InterPaint |
| IPL | Pantone Spot reference palette file | CorelDRAW |
| IPN | Intecplan project | Intecplan Business Plan Software |
| IPS | IPS Patching Format (International Patching System) | Rom hacking community |
| IPT | Part file | Autodesk Inventor |
| IPT | MultiColor Image | InterPaint |
| IRRMESH | static irrMesh files | |
| IRS | Resource (WordPerfect) standard.irs | WordPerfect |
| IRT | Data | IRIT 3D model |
| IRTR | Graphicon-2000 Interactive Real-Time PHIGS | |
| ISD | Spelling Checker dictionary | RapidFile |
| ISH | Archive | ISH |
| ISMA | Output Video file | Islam Abusa'a Software |
| ISO | ISO-9660 table | see: List of ISO image software |
| IST | Digitrakker Instrument File | AWAVE |
| IT | Impulse Tracker music file | Impulse Tracker |
| IT | Settings | intalk |
| ITF | Interface file | JPI TopSpeed Pascal |
| ITL | iTunes music library | |
| ITN | Itinerary file | TomTom PNDs |
| ITT | IconTweaker Theme | |
| IV | SGI Inventor | |
| IV-VRML | Inventor VRML Format | |
| IVE | OpenSceneGraph 3D model | |
| IVI | Image file | ImmerVision |
| IVL | Lensflare file | ImmerVision |
| IVP | Panorama file | ImmerVision |
| IVU | User Interface file | ImmerVision |
| IW | Presentation flowchart | IconAuthor - HSC InterActive |
| IWA | Text file | IBM Writing Assistant |
| IWB | Information WorkBench | Prodeo |
| IWD | Call of Duty Map - Game Data Archive | Activision, Inc. |
| IWP | Text file | Wang |
| IX | data | dtSearch index |
| IZT | Izl binary token file | IZL |
Read more about this topic: List Of File Formats (alphabetical)