# IMG (file format)
An IMG file is a raw disk image: a byte-for-byte, sector-by-sector copy of the contents of a storage device such as a hard drive, floppy disk, [USB flash drive](https://www.edgepedia.org/usb-flash-drive), [SD card](https://www.edgepedia.org/sd-card), or optical disc, stored as a single file with no compression, no metadata, and no container header.[1](https://whatthisfile.com/file/img/) • [2](https://www.reformatly.com/fileformats/img.html) The file contains exactly the data in the order it appears on the source disk, from the first sector to the last.[1](https://whatthisfile.com/file/img/)
| Key fact | Detail |
|---|---|
| Content | Exact byte-for-byte copy of a storage device: hard drive, floppy disk, USB flash drive, SD card, or optical disc[2](https://www.reformatly.com/fileformats/img.html) |
| Structure | No compression, metadata, or container format; just raw data in the order it appears on the physical disk[1](https://whatthisfile.com/file/img/) |
| Whole-disk image | Includes the partition table (MBR/GPT) and all partitions; a single-partition image starts at the partition's first sector[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html) |
| Typical uses | Raspberry Pi SD card backups, USB drive clones, OS flashing images, virtual machine disks[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html) • [4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/) |
| Origins | Originally associated with disk image files created from floppy disks[5](https://www.file-extensions.org/img-file-extension) |
| Emulator support | Raw is the default disk image format in QEMU, chosen for simplicity and easy export to other emulators[6](https://www.qemu.org/docs/master/system/images) |
| Other meanings | The .img extension is also used by Grand Theft Auto game data, Garmin map files, ERDAS IMAGINE raster images, and GEM images[7](https://fileinfo.com/extension/img) |
## What the file contains
Because an IMG file is a raw copy, what it holds depends entirely on what was captured. A whole-disk image includes the partition table (MBR or GPT) and all partitions. A single-partition image starts at the partition's first sector and contains only that filesystem.[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html) The contents are otherwise dependent on the filesystem of the disk that was imaged.[8](https://docs.fileformat.com/disc-and-media/img/)
The format is filesystem-agnostic: the imaging program copies whatever data is on the source disk without interpreting it, so the same extension covers floppy, hard disk, USB, and optical images.[9](https://win32diskimager.org/what-is-an-img-file-explained/) • [4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/) Some IMG files are bootable and some are not, depending on the data they contain.[4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/)
## How it is created and used
Because the file is raw, it is usually written back to a device rather than opened as an archive: you write an IMG to a USB stick or SD card instead of extracting files from it.[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html)
Common uses include:
- Writing Linux distribution images directly to USB drives, where the image contains the full disk partition structure[4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/)
- Backing up Raspberry Pi SD cards and cloning USB drives[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html)
- Installing and accessing older operating systems such as MS-DOS in virtual machines, a use inherited from floppy disk images[7](https://fileinfo.com/extension/img)
- Serving as virtual hard disks in emulators; QEMU treats raw as its default format and notes that on filesystems supporting holes (such as ext2, ext3, or NTFS) only the written sectors reserve space[6](https://www.qemu.org/docs/master/system/images)
A raw image of a disk or partition is a larger file than a regular (non-raw) disk image of the same disk and takes longer to create.[10](https://www.disk-image.com/downloads/DiskImageUserGuide.pdf)
## Comparison with other image formats
IMG belongs to a family of disk image formats that differ in structure and compatibility.[4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/)
- **ISO** is a byte-for-byte copy specifically of CD/DVD media using the [ISO 9660](https://www.edgepedia.org/iso-9660) filesystem, and is the most widely supported: Windows can mount it directly. Strictly speaking, an ISO is an IMG with the additional constraint of an ISO 9660 filesystem inside.[11](https://win32diskimager.org/img-vs-iso-vs-bin-file-format-differences/)
- **BIN** stores raw disc data and is usually paired with a CUE file, a text sidecar describing the track layout, which is needed for multi-track CDs such as audio or game discs.[11](https://win32diskimager.org/img-vs-iso-vs-bin-file-format-differences/) • [12](https://docs.libretro.com/guides/disc-images/)
- **DMG** is a macOS container supporting compression, encryption, and read/write variants, but is a portability barrier outside macOS.[3](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html)
For optical media, raw formats such as DD, IMG, and BIN store the exact 2352-byte sector sequences on the disc, including error-correction data, while an ISO stores only the 2048 bytes of user data per sector.[13](https://archive.nyu.edu/bitstream/2451/43877/2/Schweikert_OpticalMediaPreservationNYU_2018.pdf) Multi-track disc images, including CD-Audio discs, can be stored in formats such as CUE/BIN, CCD/IMG, and MDS/MDF.[14](https://www.histo.cat/mini/e/ISO-vs.-IMG-and-NRG-formats)
Windows does not always mount IMG files automatically because they are not as standardized as ISO files; some can be mounted with third-party tools and some can be converted to ISO.[4](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/)
## Security consideration
Although .img files contain only static data, disk images have been used to distribute malware: as with ISO files, an image once mounted can appear as a drive with autorun behavior and conceal a program capable of evading certain "mark of the web" download alerts.[15](https://www.file-extension.info/format/img)
## Other uses of the .img extension
The extension is shared by several unrelated file types. Seven file types use .img, including:[7](https://fileinfo.com/extension/img)
- **Grand Theft Auto data files**: game data for GTA III and IV, stored as gta3.img in GTA III, Vice City, and San Andreas, with three format versions across those games; modders edit them with tools such as IMG Tool, SparkIV, and OpenIV[7](https://fileinfo.com/extension/img)
- **Macintosh disk images**: used by [Mac OS 9](https://www.edgepedia.org/mac-os-9) and earlier, later replaced by the .DMG format[7](https://fileinfo.com/extension/img)
- **Garmin map files**: map data such as street names, navigation routes, and points of interest for Garmin GPS devices[7](https://fileinfo.com/extension/img)
- **ERDAS IMAGINE image files**: geospatial raster images using the ERDAS Hierarchal File Format (HFA)[7](https://fileinfo.com/extension/img)
- **GEM images**: raster images from the 1980s Graphics Environment Manager by [Digital Research](https://www.edgepedia.org/digital-research), holding monochrome, grayscale, or color images of up to 16 colors[7](https://fileinfo.com/extension/img)
Because the same extension covers unrelated formats, identifying the creating program matters: an IMG from an old rendering package needs an image viewer, while one from a disk, emulator, GPS device, or OS download should be handled as a disk image.[16](https://www.openwith.org/file/img)
## References
1. [What is a .img file? — WhatThisFile](https://whatthisfile.com/file/img/)
2. [IMG Format - Disk Image | Reformatly](https://www.reformatly.com/fileformats/img.html)
3. [Disk Image Formats Explained: ISO vs DMG vs IMG vs BIN/CUE | VIOware Guides](https://www.vioware.com/knowledge/disk-image-formats-iso-dmg-img-bin-cue.html)
4. [What Is an IMG File? ISO vs BIN vs CUE vs IMG | GeeksDigit](https://www.geeksdigit.com/iso-vs-bin-vs-cue-vs-img-disk-image-formats-explained/)
5. [IMG file extension - file-extensions.org](https://www.file-extensions.org/img-file-extension)
6. [Disk Images — QEMU documentation](https://www.qemu.org/docs/master/system/images)
7. [IMG File - FileInfo.com](https://fileinfo.com/extension/img)
8. [IMG - Disk Image File Format | docs.fileformat.com](https://docs.fileformat.com/disc-and-media/img/)
9. [What Is an IMG File? Disk Image Formats Explained | Win32 Disk Imager](https://win32diskimager.org/what-is-an-img-file-explained/)
10. [Disk Image User Guide](https://www.disk-image.com/downloads/DiskImageUserGuide.pdf)
11. [img vs iso vs bin:format differences explained (2026)](https://win32diskimager.org/img-vs-iso-vs-bin-file-format-differences/)
12. [Disc Images: CUE, CHD and M3U - Libretro Docs](https://docs.libretro.com/guides/disc-images/)
13. [Optical Media Preservation, NYU (Schweikert, 2018)](https://archive.nyu.edu/bitstream/2451/43877/2/Schweikert_OpticalMediaPreservationNYU_2018.pdf)
14. [ISO vs. IMG and NRG formats - Institut Nova Història](https://www.histo.cat/mini/e/ISO-vs.-IMG-and-NRG-formats)
15. [IMG File - File-Extension.info](https://www.file-extension.info/format/img)
16. [IMG file - Open With](https://www.openwith.org/file/img)
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*Topic: Encyclopedia › Sports, games, and recreation › Video games and digital play › Platforms and hardware › Emulation and preservation › ROM images and dumping*
*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license