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HOME TOPICS ABOUT ME Convert those JPEGs to a lossless format as soon as you get them out of the camera. |
technofile Al Fasoldt's reviews and commentaries, continuously available online since 1983 How to save 'lossless' images even if your camera uses JPEGsOct. 7, 2001 By Al Fasoldt Copyright © 2001, Al Fasoldt Copyright © 2001, The Post Standard My recent article about the pitfalls of JPEG images left a lot of readers with questions about the way their digital cameras save pictures. I got dozens of letters about that single topic in a few days. This week I'll try to explain what you should do if your camera saves its images as JPEGs. I pointed out in the previous article (available at twcny.rr.com/technofile) that some methods of storing digital images degrade the image quality. The most common of all the "lossy" methods is JPEG (also called JPG, and pronounced "jay-peg" in both cases). I strongly recommended that anyone who takes pictures with a digital camera use a lossless method instead. The standard no-loss method for Windows users is the BMP ("bimp") format. The only drawback to BMP images is file size. Because they are not compressed in any way, BMPs can be huge. That's why I recommended PNG ("ping"), a relatively new lossless image format, as an alternative to BMP and JPEG. PNG is better than BMP because PNG images are compressed to about a third the size of those images. PNG is better than JPEG because PNGs are not damaged in any way by the method of compression. The entire image is fully restored when your software opens a PNG image for viewing or editing. Another advantage PNG has over BMP: While BMP is mostly a Windows format, PNG is a universal format. Anyone with a modern Macintosh, Linux PC, BeOS PC or Unix computer can create and save images in the PNG format. That's all fairly straightforward. But I unintentionally confused many of you by saying you should always choose a lossless method instead of JPEG for your digital images. What are you supposed to do if you have no choice? Suppose your camera automatically saves images as JPEGs before you ever see them? I should have seen this conundrum coming, because my camera works the same way. When I plug the camera into my PC to extract the latest photos from its memory, I get a bunch of JPEGs. I have no choice. And if that's your situation, you are I are in the same digital boat. The solution is simple: Convert those JPEGs to a lossless format as soon as you get them out of the camera. I do this with ACDSee, the king of Windows image utilities. I realize there are many other ways to convert images from one format to another, and I have four or five other programs that can do it well. But no program does image conversion the way ACDSee does it. It is superb. (I simply select all the JPEGs in the ACDSee file browser, click my right mouse button and choose "Convert." It does all the rest.) Irfan View is another program that does this well. And, unlike ACDSee, it's free. You'll find reviews of both of them on my site. The fact that you and I are stuck with JPEGs as the original image format doesn't mean we should stick with JPEGs once they are out of the camera. That's why I am telling you to save them as PNGs as soon as you get them onto your hard drive. Once you've done that, forget the JPEG versions. Work only with the PNGs. But don't let that advice get in the way of another important task. Always take your pictures at the highest quality the camera allows. I can't think of any reason why we should settle for a low-quality image. Sure, you can take more pictures if you set the camera's image quality to something other than the highest choice. But why? We need all the quality we can get. |