The new iMac bulges in the back, however. Schiller did not say how much.
The new model achieves its severe thinness in part by eliminating the optical disc drive. Apple has been leaving those drives out of its most recent laptop models as well. The original iMac was one of the first computers to lack a floppy disk drive, something that is now rare among PCs.
An iMac model with a 21.5-inch screen will start shipping in November for $1,299 and up, Schiller said. A 27-inch version will start at $1,799.
Apple also introduced its Fusion Drive, which combines flash and hard drive storage in one interface. In doing so, the hybrid combines the faster speed of flash memory and the higher capacity of regular hard drives. Apple says it's nearly as fast as flash memory on its own and is available as an option instead of the regular hard drive.
As Schiller introduced the new iMacs, he showed on a giant display how the iMac has shrunk over the years.