Thursday, August 16, 2012

JPEG is a “lossy” compression algorithm

Friends don't let friends shoot JPG. At least shoot RAW plus JPG! Lisa

http://www.petapixel.com/2012/08/14/why-you-should-always-rotate-original-jpeg-photos-losslessly/

"JPEG is a “lossy” compression algorithm that’s geared towards storing and sharing photos without taking up too much disk space. Rotating these compressed images is usually done by decompressing, rotating, and then re-compressing. Since the re-compression is lossy (i.e. data is thrown away), this process results in slightly degraded photos (hence that warning)."


If you’re not convinced, check out this interesting experiment done by a Wikipedia user named Burny. Using a simple computer script, he took the following image and rotated it lossily 2000 times:
Why You Should Always Rotate Original JPEG Photos Losslessly 0 mini
Here’s hows the image degraded through those 2000 rotations:
Why You Should Always Rotate Original JPEG Photos Losslessly 200 mini
Why You Should Always Rotate Original JPEG Photos Losslessly 500 mini
Why You Should Always Rotate Original JPEG Photos Losslessly 900 mini
Why You Should Always Rotate Original JPEG Photos Losslessly 2000 mini
Pretty crazy, huh?

http://www.petapixel.com/2012/08/14/why-you-should-always-rotate-original-jpeg-photos-losslessly/

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