| Abbreviation | Definition |
|---|---|
| ICN | Icon language source code file |
| ICN | RIP icon Graphics file |
| ICO | Icon image file |
| ICON | Icon image (1bit) (Sun icon file) (Unix) |
| ICP | Parameter file (IContact) (Unix) |
| ICR | Bitmap graphics (NCSA Telnet Interactive Color Raster graphic file) |
| ID | Disk IDentification file |
| IDB | IDA Database |
| IDC | IDA C language source code file |
| IDC | Internet Database Connector Document |
| IDC | Tech CORE IDC file Bitmap graphics |
| IDD | MIDI Instrument Definition |
| IDE | Borland C++ 4.x Project file |
| IDF | MIDI Instrument DeFinition |
| IDK | OS/2 Saved SKF Format |
| IDL | Interface definition file (Visual C++) |
| IDS | IDA Imported Names Format |
| IDW | Vector graphics (IntelliDraw) |
| IDX | Header information (CMYK image) (Stork format) |
| IDX | Index (many - FoxPro) |