: How many times can I open and resave a jpeg until its quality noticeably drops? This isn't a problem I'm currently facing, rather just a curious thought. I know that every time you open and

@RJPawlick971

It depends...


on the image
the resolution of the image
the software saving the JPG
the amount of compression you are using on the JPG
the opinion of the person looking at the image

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@Hamaas979

I once worked for a multimedia company where a graphic-artist was tasked with this exact question. Her findings were:


A jpeg can be compressed up to 1/10 of the original bitmap (bmp) without any distinguishable* changes.
Such a jpeg can be re-saved up to three times at the same compression level, without any distinguishable* artifacts.


*distinguishable: to a 'normal' 'regular' human viewer, without magnifying the image.

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@Michele215

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.)


1-Jpeg degradation by Connecticut State Library


2-JPG artifact test 1000 saves by Martin Flucka


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. hadto.net/sketchbook/generation-loss/
I'm sure there are more out there.

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@Goswami567

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.

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