Seadragon Mobile is free to download from the iTunes store
Microsoft has launched a freeware graphics viewer for iPhone users.
Seadragon Mobile lets users view large images on their iPhone with "just a few taps of your finger".
Developed by Live Labs, Seadragon Mobile is the first in a number of planned Microsoft iPhone applications.
Although Apple and Microsoft are market rivals, the firm chose the iPhone ahead of other mobile devices because of the phones popularity and graphical capabilities.
Talking to Todd Bishop's Microsoft Blog, Alex Daley, group product manager for Microsoft Live Lab said the iPhone was the obvious mobile choice for Seadragon.
"The iPhone is the most widely distributed phone with a (graphics processing unit)," said Mr Daley.
"Most phones out today don't have accelerated graphics in them. The iPhone does and so it enabled us to do something that has been previously difficult to do."
"I couldn't just pick up a Blackberry or a Nokia off the shelf and build Seadragon for it without GPU support," he added.
Seadragon is the engine that drives Microsoft's photo-browsing software, Photosynth. Designed for viewing large images over the internet, it works by storing multiple resolutions of the file.
It is thought Microsoft will release voice recognition software for the iPhone in 2009.