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How many times can I open and resave a jpeg until its quality noticeably drops?


Question

This isn't a problem I'm currently facing, rather just a curious thought.

I know that every time you open and resave a jpeg it will lose information, How many time could you do this until there is a noticeable difference? 10/100/1000 times?

2015/03/17
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3/17/2015 12:19:00 PM

Accepted Answer

I've seen a video featuring this. I'm not sure what it was anymore, but check out these 3 videos (from YouTube and Vimeo):

(The images aren't hyperlinked. Instead, there are linked texts at the bottom of each.)

Jpeg degradation by Connecticut State Library
1-Jpeg degradation by Connecticut State Library

JPG artifact test 1000 saves by Martin Flucka
2-JPG artifact test 1000 saves by Martin Flucka

Generation Loss by hadto
3-Generation Loss by hadto This last one by hadto on Vimeo also has a code (for the programming language "Processing") to achieve the same. http://hadto.net/sketchbook/generation-loss/

I'm sure there are more out there.

2015/03/17
7
3/17/2015 1:15:00 PM

There is no simple answer - each compression event dumps some data, it tends to dump less with subsequent saves as most of the disposable data has already been disposed of. Factors include the compression level, the size of the image, it's content, your personal threshold of "noticeable" and the quality of your monitor.

2015/03/17