Microsoft has entered the iPhone application market Saturday, with the launch of its Seadragon Mobile image browsing software.

The app lets users easily navigate through large images, or image collections, using the Apple iPhone's touch-screen interface.

"Want to see giga-pixel images on your iPhone? Now you can--with Seadragon mobile," wrote a company blogger on Microsoft's Live Labs site, in a Saturday post. "Seadragon Mobile brings the same smooth image browsing you get on the PC to the mobile platform," the blogger promised.

According to the blog, Seadragon Mobile lets users scroll through, and zoom in on, maps or photos "with just a few pinches or taps of your finger." The app is specifically designed to enable navigation through large images built using Microsoft's Photosynth technology.

Photosynth lets users stitch together separate images into a continous whole to create panoramic pictures.

To date, Microsoft has held off introducing apps for the iPhone--preferring instead to focus on its own Windows Mobile platform. It appears, however, that Microsoft can no longer simply ignore the iPhone's market dominance.

But even some Microsoft employees are wondering why the company did not first release Seadragon Mobile for Windows Mobile. "It's terrific to see this innovation coming out but I have to ask myself where is the Windows Mobile version?" wrote Steve Clayton, a Microsoft technology manager who works on software and services projects, in his own Saturday blog post. "Surely phones like the touch HD from HTC would benefit from this too?" wrote Clayton.

Still, Clayton seemed impressed with his colleagues' work. "The app is astonishing, the aerial maps with Seadragon and GPS enabled are a joy to behold," he wrote.