简单wiki了一下：
The IMG file format is one of the following files:
1.A CD or DVD image file, essentially equivalent to an ISO file. On such a file, simply changing the extension from IMG to ISO can make it usable as the latter by most programs.
2.An archive format used for creating a disk image of floppy disks and HDDs. This allows for digital storage, transmission, and replication of floppy disks and HDDs. Files created using this format typically use the ".IMG" file extension. There are different, incompatible image formats which use the .IMG extension.
3.A file in the Macintosh Disk Image format used by Aladdin Systems (now Allume Systems) ShrinkWrap and Apple Disk Copy for Mac OS although they share the same file extension.
4.The IMG file format, also known as GEM IMG, is an image file format used to store bitmap digital images on Graphical Environment Manager.
5.A graphics image format used in various ways by many different graphics software packages.
6.A map file format used by Garmin GPS devices.
如果是1的话，也就是改了扩展名的iso可以使用IMAPI
http://msdn.microsoft.com/en-us/library/windows/desktop/aa366450(v=vs.85).aspx
The IMG file format is one of the following files:
1.A CD or DVD image file, essentially equivalent to an ISO file. On such a file, simply changing the extension from IMG to ISO can make it usable as the latter by most programs.
2.An archive format used for creating a disk image of floppy disks and HDDs. This allows for digital storage, transmission, and replication of floppy disks and HDDs. Files created using this format typically use the ".IMG" file extension. There are different, incompatible image formats which use the .IMG extension.
3.A file in the Macintosh Disk Image format used by Aladdin Systems (now Allume Systems) ShrinkWrap and Apple Disk Copy for Mac OS although they share the same file extension.
4.The IMG file format, also known as GEM IMG, is an image file format used to store bitmap digital images on Graphical Environment Manager.
5.A graphics image format used in various ways by many different graphics software packages.
6.A map file format used by Garmin GPS devices.
如果是1的话，也就是改了扩展名的iso可以使用IMAPI
http://msdn.microsoft.com/en-us/library/windows/desktop/aa366450(v=vs.85).aspx
