The photos first appeared on this flickr account and have since been widely syndicated across the web. One photo reveals that the new keyboard, which appears to be a pre-production unit, carries the codename "M89."
Historically, Apple has used an "M" prefix to reference peripherals that are under development and a "Q" prefix for computer systems. For example, the company's original Mighty Mouse design was frequently referred to as "M18" prior to its release.
Earlier this month, AppleInsider exclusively reported that Apple's upcoming makeover to the iMac line would include new super-slim external keyboards.
Sources familiar with the matter had said the new peripheral would sport an aesthetic and feel similar to the low-profile keyboards used in Apple's 13-inch MacBook notebooks.
Apple is widely expected to take the wraps off its next-generation iMacs in the coming weeks. For more on what to expect from the new systems, please see AppleInsider's previous coverage: