Picasa Gets Sharper Images

Picasa hasn't been able to take on Flickr's coolness factor, which it managed to retain to a certain degree even after being acquired by Yahoo, but Google's photo sharing service has it's own strengths and what it lacks in charm it makes up in smartness. Most recently, developers have taken advantage of the performance improvements in the online front-end to serve better quality images with no penalty when it comes to loading times.

"A helpful feature of Picasa Web Albums is that when you view photos, they're automatically resized to fit your browser. We always display the largest-size photo that will fit inside your browser window, up to 1600 pixels if you have a nice big display," Thomas Kang & Jon Wray, software engineers at Google wrote.

"From our extensive testing, we found that adding a little bit of sharpening can make a subtle but noticeable improvement in the visual quality of resized photos in Picasa Web Albums. So we recently added some logic to the server processing code that adds the appropriate amount of sharpening when necessary, before sending it out to the browser," tgey added.

In order to enable Picasa to serve the appropriate size image for the browser window, Google stores a few smaller copies of the original image which is usually capped at 1600 pixels. Picasa then determines which of the stored copies is the closest to the size it needs to display and then resizes it on-the-fly again if necessary.

Because of Google's speed obsession, up till now, Picasa didn't do any other kind of processing on the image before sending it out so it wouldn't slow down the process. Recently though, a number of performance improvements have been implemented, giving developers a little head room and enabling them to add a sharpening filter to the resized images. The resize algorithms usually make the images a little blurry as smaller details get smudged into background. Applying a sharpening filter can improve the quality of the details without distorting the image too much. For now, the filter is applied only to new uploads and the smaller size images, but the Picasa team says it will roll out similar improvements affecting the quality of the images in the future.