ISO and IMG are file formats used to distribute disc images. While ISO is locked to the ISO 9660 optical disc format, IMG is a raw copy of any sector layout, supporting floppy disks, hard drives, and flash keys.
Both are raw, uncompressed containers, meaning extraction speeds are limited only by your drive read/write bandwidth.
| Feature | ISO Format | IMG Format |
|---|---|---|
| Optical Disc Lock | Yes (specifically CD/DVD layouts) | No (any disk sector copy) |
| File System Standard | ISO 9660 / Joliet / UDF | FAT, NTFS, ext, or raw binary |
| Floppy Disk Support | No | Yes |
| Structure | Sector sizes always 2048 bytes | Variable sector sizes |
| Primary Use | Operating system installers | Raspberry Pi cards / floppy backups |
ISOs are natively mounted by Windows and macOS. IMGs are often used by flashing tools like Rufus or BalenaEtcher to write bootable files directly to USB drives.
Both can run auto-run malware if mounted. Unpacking them using iLoveExtract allows you to look at files safely without mounting them.
Only if the IMG file contains an ISO 9660 file system structure. Otherwise, the OS will fail to mount it.
You can extract files from an IMG using archive tools or flash it to a drive using card-writing utilities.
ISO compression speeds depend on the compression level and dictionary sizes used. Generally, ISO uses simpler dictionaries which makes it faster, while IMG focuses on achieving a tighter compression ratio at the cost of speed.
ISO is supported natively on most systems, while IMG files often require downloading separate utility apps or using web tools like iLoveExtract to open them.
Yes, both formats support file encryption. However, IMG typically supports AES-256 encryption, which is much stronger than older encryption algorithms sometimes found in ISO formats.
No, both formats use lossless compression algorithms. Converting between them extracts the files exactly as they are and packages them without losing any data.
ISO files have smaller header sizes, meaning they have less metadata overhead for single files. For large directory structures, IMG files organize headers more efficiently.
This depends on the formats. Many modern compression formats are open-source, whereas proprietary formats may require licensing or specific software binaries to write files.
The file size exceeds the supported safety limit.