Digital cameras have liberated awe-struck travelers and proud parents from worrying about the price of film processing. But showing off those megapixels of memories is still reminiscent of tedious living room slideshows _ and perhaps now worse, because instead of one blurry photo of the Eiffel Tower or the high school musical, there might be 50.

Most digital photo-sharing sites require viewers to click from an album to a bite-sized thumbnail of a picture, and then again to a large image, then sit through a slideshow of snapshots one by one. Microsoft Corp.'s newest Web tool, Photosynth, is designed to give viewers a much zippier way to take in the sights of Paris or an act of "HMS Pinafore."

Here's how it works: After a quick software download, the photographer selects a collection of related images from her hard drive. The software crunches the files using the local computer's processing power, looking for pixels that are the same in each photo. Then, Photosynth stitches together the images into a panoramic scene.

There is an old-school analog to this: taped-together photo prints. But online the result is part photo gallery, part movie. One photo is shown clearly at a time; adjacent images appear faded, and others less closely related to the photo in focus are indicated with a ghostly scatter of pixels. Viewers can zoom in and out, and pan left and right, through the scene created by overlapping many different views of the same place or object.

The software, which works only on Windows PCs, latches on to similarities and ignores differences, so photos taken in the same room but at different times of day with different inhabitants can still match up.

Microsoft first opened Photosynth to employees and partners including the National Geographic Society, so the site already has many "synths" on file. (Those "synths" are all given numeric "synthy" scores, indicating how many of the photos overlapped in a way the program could detect.)

One synth, from a National Geographic photographer, combines hundreds of images of Stonehenge; another, submitted by a Microsoft employee, lets the viewer follow a climber on a harrowing ascent of a rock face.

Synths can be embedded like videos into other sites, including blogs and eBay auction listings.

Photosynth, which was due to launch late Wednesday, doesn't yet allow more than one person to add photos to a "synth," which means strangers can't easily pool photos of a certain place or event, as is commonly done using tags on sites like Yahoo Inc.'s Flickr.

But Microsoft's David Gedye, manager for the Live Labs group that cooked up Photosynth, said eventually the program should allow not only small-scale collaborations but also global photo contributions. Those could be fed into Microsoft's mapping technology to fill in gaps where satellite images aren't available.

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On the Net:

http://www.photosynth.com