PetaPixel

Saving JPEG Photos Hundreds of Times

Most of you probably know that JPEG is lossy compression method, meaning compression permanently throws out data and detail. Luckily, a typical compression can save 10 times the space of an uncompressed image without sacrificing much noticeable quality. However, if the image is repeatedly compressed and saved, artifacts introduced during compression become more and more obvious.

Reddit member Grundle decided to see what repeated compression looks like by saving the same image over itself 500 times at high quality (10/12 in Photoshop). He then combined the images into the following video:

10 months ago another Reddit member elezeta did the same experiment, compressing a JPEG 600 times:

I think it’s pretty clear why you should always work with RAW files if you care about the quality and longevity of your work. Every time you save those JPEG photographs, you lose a little piece of awesomeness.


 
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  • JessicaLum

    The bottom one looks like a Magic Eye 3D illusion by the end.

  • http://shuttersounds.thedailynathan.com nathanyan

    The point isn't that you should always work with a RAW file necessarily, it's that you should always work with the source files. Yes the images demonstrate artifacting, but nobody in their normal use will resave an image 500 to 600 times.

    If you are always making edits starting from the source image (and using a non-destructive tool such as Lightroom, Aperture, or ACR, you'll do that whether it's RAW or JPEG), your output image will always be saved just once from the source image. And compressing once in JPEG has virtually no perceptible loss.

    If you want to try this, take the source image, re-save once, load both into Photoshop or GIMP, layer one on top of the other, and use a difference blending. The resulting image will be black, indicating that there is no pixel-value difference between the files.

    Alternatively you could export both as ppm and use a text diff to verify that all pixel values are the same.

  • http://www.paulpetch.com www.paulpetch.com

    nathanyan speaks da' troof!

  • mtungate

    I don' t think that is really a valid test to show how “lossy” a .jpg is. I don't remember the last time I saved a .jpg 500 times. For 99.9% of the time a .jpg is fine after your done editing your raw. What is the point of this test unless it is purely for artistic purposes.

  • http://www.petapixel.com Michael Zhang

    I think the tests were more to answer the question, “Hmm… I wonder what a JPG looks like after ### compressions”? You're right in that this has nothing to do with how good or bad JPEG is in terms of compression.

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  • jay pegg

    I can accomplish this same effect by saving as jpeg just once with MS Paint

  • E.G.

    Rather:

    “I think it’s pretty clear why you should always {develop archival prints of your digital photos and store them in acid-free archival folders in a dark dry place} if you care about the quality and longevity of your work.”

    That, ultimately, is what will do it. I can guarantee that a file, RAW or otherwise, will be virtually unusable in a decade or two unless you keep on updating. And, frankly, once you're dead and gone (not to be too blunt about it), there is a minimal chance that you'll be updating your digital archive.

    Print 'em. Store 'em. Make sure that someone knows where they are.

  • http://shuttersounds.thedailynathan.com nathanyan

    Well if you use cloud storage, the level of redundancy there means your files will last forever, essentially.

    You also neglect that printing out your images is requires a digital to analog conversion, and another analog to digital conversion to get it back into a digital file. So there's going to be some loss there, not to mention that you'd have to print from a TIFF or JPEG render of the RAW file to even do that, losing a bunch of the original RAW information.

  • http://digitizor.com Ricky

    yay for MS Paint :p

  • http://twitter.com/Clisint Bjarke

    Am I the only one that is actually impressed by how well the first image i preserved after 500+ compressions? Yes the background become grainy and the typical “blocks” from the JPEG compression are evident. But the face still looks pretty good.
    And as Nathanayan already mentioned it is very rare that an image is resaved (and recompressed) 500 times.

  • http://www.xamuel.com/ Xamuel

    The bottom one, near the end, starts to look like some of the “graphics” from old CGA video games ;)

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  • bjw

    The face is well preserved because the compression happens in the areas where there is little variation. So, if we are mad enough to do 500 compressions, we lose the dull part of the picture, and keep the interesting part.

  • http://photo.ecothinking.org/ Jonathan

    Although the compression will be for the worse it isn't necessarily inherent of the JPEG. There was another blog that showed that if you compare how you save the JPG you'll have different results. For instance if you save in Photoshop, you'll have worse results. Here's the link. http://bit.ly/cShovU

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  • http://www.ricardogalvao.blogspot.com/ ricardo galvão

    If you work with .jpeg this way…
    .RAW is for you…
    Just one question:
    Do you print in .RAW?
    even in 16 bit?
    Oh, no? if you do not print in raw
    why underestimate .JPEG?
    I never use .raw…(in analog film times i used Chrome film, i could not have a mistake)
    as JPEG..

    thanks

    sorry my bad english

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  • jimgoldstein

    Here is another take on the same evaluation with a variety of patterns and photos to display the impact after 8, 16, 32, 64, 128, 256 and 1024 rounds of compression. No video, but this has been online since 2005.

    http://www.jmg-galleries.com/articles/jpeg_comp

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  • shawn

    So? If I microwave food in a Chinese food container 500 times, that might degrade, too. JPGs are meant to be exported once, and when used correctly, they’re great. Can you edit a JPG? Sure, maybe 1-2 times. I don’t know anyone who would save their files like this over and over again.

  • JadedUnknown

    MIDI and GIF files have been around for over 2 decades. Try again.

  • SuperCritic

    Raw? Why not png?

  • Jeremy Schneider

    Stop it with all of your reasoned thought and rationality. RAW4EVA!!!