| Extension | Description | File Type |
|---|
| i00 | DVD Shrink Seperation File | Disk Image Files |
| i01 | Disk Image Split File | Disk Image Files |
| i3d | Micrografix Simply 3D File | 3D Files |
| iaf | Outlook Account File | Settings Files |
| iam | Autodesk Inventor Assembley File | 3D Files |
| ibd | Installer Dialog Resource File | Misc Files |
| ibp | Isobuster Image File | Disk Image Files |
| ibq | Isobuster Managed Image File | Disk Image Files |
| ibt | IBtracer File | Game Files |
| ica | Citrix Independent Computer Architecture File | Settings Files |
| icd | SafeDisc Encrypted Executable File | Encrypted Files |
| icf | Conexant ADSL Modem Configuration File | Settings Files |
| icl | Icon Library File | Misc Files |
| icm | Image Colour Matching | Settings Files |
| icns | Icon File | System Files |
| ico | Icon File Format | Graphic Files |
| ics | iCalendar Calendar File | Data Files |
| id | Lotus Notes User ID File | Misc Files |
| id2 | Windows Live Messenger Emoticon File | Data Files |
| idcl | Inventor Desktop Content File | Data Files |
| ide | Inventor iFeature File | 3D Files |
| idf | Instrument Definition File | Audio Files |
| idlk | InDesign Lock File | Settings Files |
| idn | Infrared Digital Negative File | Graphic Files |
| idx | Index File | System Files |
| iff | Interchange File Format File | Data Files |
| ifo | DVD Information File | Video Files |
| ifp | Knowledgeman Script File | Developer Files |
| ifx | Rational XDE File | Developer Files |
| igs | International Graphics Exchange Specification File | CAD Files |
| iif | Quickbooks Interchange File | Data Files |
| iks | InSeine Document File | Misc Files |
| ima | Floppy Disk Image File | Disk Image Files |
| image | Disk Copy Image File | Disk Image Files |
| img | Image File | Disk Image Files |
| imp | Audition Convolution Reverb Effect File | Audio Files |
| in | CFAST Input File | Misc Files |
| inc | Include Files | Developer Files |
| ind | Adobe InDesign Document File | Layout Files |
| indd | Adobe InDesign File Format | Desktop Publishing |
| index | Index File | Misc Files |
| inf | Setup Information File | Settings Files |
| info | ZoomBrowser Index File | Graphic Files |
| ini | Windows Initialization File | Settings Files |
| init | WebMoney Temporary Key File | Misc Files |
| inp | Abaqus/CAE Input File | CAD Files |
| ins | Inspiration File | Data Files |
| install | Installation Text File | Text Files |
| int | Borland Delphi Interface File | Developer Files |
| inx | InDesign Export File | Desktop Publishing |
| ion | Description File | Text Files |
| ip | IconPackager Icon Set File | Graphic Files |
| ipa | iPod/iPhone Application File | Executable Files |
| ipd | BlackBerry Backup File | Backup Files |
| ips | Patched Game File | Game Files |
| ipsw | IPod/IPad/IPhone Software File | Archived Files |
| ipt | Autodesk Inventor Part File | 3D Files |
| iri | IR Image File | Graphic Files |
| irp | InfraRecorder Project File | Misc Files |
| irx | Brewer Irradiation File | Data Files |
| isn | Installer Source Files | Misc Files |
| iso | Disk Image File | Disk Image Files |
| iss | InstallShield Silent Response File | Settings Files |
| isu | InstallShield Uninstaller Script File | Executable Files |
| isz | ISO Zipped File | Disk Image Files |
| itc2 | iTunes Album Data File | Graphic Files |
| itdb | iTunes Database File | Data Files |
| ithmb | iPhone/iPod Thumbnail File | Graphic Files |
| itl | Music Library File | Data Files |
| itr | Icy Tower Replay File | Game Files |
| itx | ITX Form Template | Data Files |
| iwd | Call of Duty Game Data File | Game Files |