Is it true that I lose image quality every time I rotate or resave JPEG images from my digital camera?
Scott Edelman, via e-mail
Senior Associate Editor Melissa J. Perenson responds: The JPEG format uses lossy compression, so whenever you change an image and resave it as the same file, it will be recompressed, which in turn can lead to noticeable image degradation. Not all imaging apps support lossless JPEG rotation; those that do–including ACD Systems’ ACDSee, Apple’s iPhoto, and Breeze Systems’ BreezeBrowser–generally save a copy of the unrotated image so you can revert to the original as needed. If you shoot in JPEG, I suggest saving your edited or rotated files with a new file name. See this Digital Photo Tips column by Dave Johnson for more details.
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