What is a .img file?
Raw Disk Image · Disk image · Various · n/a
An .img file is usually a raw, byte-for-byte copy of a disk or memory card, with no compression or extra structure. It is how operating-system images for devices like the Raspberry Pi are distributed.
What is a .img file used for?
Because a raw .img mirrors a disk exactly, it has no header of its own; its first bytes are whatever was on the disk (often a boot sector or partition table). This is why there is no single magic number.
You write an .img to an SD card or USB stick to clone the disk, using a tool like balenaEtcher or Raspberry Pi Imager. Some .img files are instead old floppy or CD images.
How to open a .img file
The .img format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .img file.
Windows
- balenaEtcher
- Rufus
- 7-Zip (some images)
macOS
- balenaEtcher
- Disk Utility
- dd
Linux
- balenaEtcher
- dd
- GNOME Disks
How to convert a .img file
You can convert a .img file to iso, vhd, vmdk using a conversion tool or the export menu of an app that opens it.
.img file signature (magic bytes)
Programs recognise a .img file by the bytes at the start of the file, not by its name. These are the signatures for IMG.
| Hex signature | Offset | Note |
|---|---|---|
| (no fixed signature) | 0 | no fixed signature; a raw byte-for-byte copy of a disk |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .img file?
An .img file is usually a raw, byte-for-byte copy of a disk or memory card, with no compression or extra structure. It is how operating-system images for devices like the Raspberry Pi are distributed.
How do I open an .img file?
To write it to an SD card or USB, use balenaEtcher or Raspberry Pi Imager. To browse its files, mount it or open some images in 7-Zip.
What is the difference between IMG and ISO?
Both are disk images. ISO follows the optical-disc ISO 9660 standard; a raw .img is a plain byte copy of any disk, common for SD cards and drives.
How do I write an .img to an SD card?
Use balenaEtcher or Raspberry Pi Imager: select the .img, pick the card, and flash. This erases the card, so back it up first.
Related formats
Sources
Details on this page were checked against authoritative references: