Skip to main content
S
shoeshine stan
Participant
May 11, 2020
해결됨

JPGs open with enormous file size in Photoshop

  • May 11, 2020
  • 3 답변들
  • 12236 조회

I didn't have this problem earlier but recently Photoshop shows enormous file sizes for images.
I want to save an image for web & devices, file size 1.38 MB. After opening it in PS the file size is 39.4 MB.

Firstly, when I choose save for web & devices I get a warning that the functionality isn't suitable for files that size.
Second, after saving it at 80% quality, progressive JPG, I have a file size on my PC of 1.34 MB instead of the original 1.38 MB. That is after saving without EXIF data. So that functionality isn't really helpful anymore.

It's the same with every JPG, no matter the original file size on my PC, Photoshop increases it massively upon opening.

Does anyone know how to avoid this?
Thanks in advance.

최고의 답변: Conrad_C

You’re almost there. You actually have two separate issues being discussed here: Photoshop “increasing” the file sizes of JPEG images, and an error when using Save for Web.

 

Photoshop “increasing” file sizes: That one’s already been discussed, but I think it’s useful to restate it. It is very common to think Photoshop is making JPEG (or other compressed) images too big, but the reality is the reverse. The natural file size of any image is what it says in the Image Size dialog in Photoshop, and that’s determined by the number of pixels and number of bits per pixel. The only reason it seems so much larger in Photoshop is that Photoshop un-compressed the compressed JPEG back up to its natural size so that it could edit it. But because everyone is used to seeing highly compressed JPEG file sizes and not uncompressed file sizes, they think Photoshop made the file size go up, when actually Photoshop is simply uncompressing the image to its natural size.

 

Save for Web error: This is completely unrelated to the issue above. This has to do with the pixel dimensions of the image (width in pixels and height in pixels, such as 3000 x 2000 px). Save for Web is very old code, written for when original images were much smaller. The large images coming out of today’s cameras have pixel dimensions so wide and tall that Save for Web sometimes can’t cope. To fix this, Adobe completely rewrote their web/mobile export code in the form of the newer command, File > Export > Export As. If you are getting that Save for Web error, try saving the same image out of the Export As command instead, which should be able to handle it easily with its more current code. By the way, that is why the Save for Web comnand has the word (Legacy) after it, because that old code is basically deprecated now, and at some unknown time in the future, Adobe is expected to remove Save for Web (Legacy) from Photoshop.

3 답변

S
shoeshine stan작성자
Participant
May 15, 2020

Thank you JJMack and D_Fosse for your explanations. I gained a better understanding of how jpg and Photoshop work.

So do I assume I just just ignore the message "The image exceeds the size Save for Web & Devices was designed for. You may experience out of memory errors and slow performance. Are you sure you want to continue?" and continue to save for web & devices anyway.

Cheers,
Stan

Conrad_C
Community Expert
Conrad_CCommunity Expert답변
Community Expert
May 15, 2020

You’re almost there. You actually have two separate issues being discussed here: Photoshop “increasing” the file sizes of JPEG images, and an error when using Save for Web.

 

Photoshop “increasing” file sizes: That one’s already been discussed, but I think it’s useful to restate it. It is very common to think Photoshop is making JPEG (or other compressed) images too big, but the reality is the reverse. The natural file size of any image is what it says in the Image Size dialog in Photoshop, and that’s determined by the number of pixels and number of bits per pixel. The only reason it seems so much larger in Photoshop is that Photoshop un-compressed the compressed JPEG back up to its natural size so that it could edit it. But because everyone is used to seeing highly compressed JPEG file sizes and not uncompressed file sizes, they think Photoshop made the file size go up, when actually Photoshop is simply uncompressing the image to its natural size.

 

Save for Web error: This is completely unrelated to the issue above. This has to do with the pixel dimensions of the image (width in pixels and height in pixels, such as 3000 x 2000 px). Save for Web is very old code, written for when original images were much smaller. The large images coming out of today’s cameras have pixel dimensions so wide and tall that Save for Web sometimes can’t cope. To fix this, Adobe completely rewrote their web/mobile export code in the form of the newer command, File > Export > Export As. If you are getting that Save for Web error, try saving the same image out of the Export As command instead, which should be able to handle it easily with its more current code. By the way, that is why the Save for Web comnand has the word (Legacy) after it, because that old code is basically deprecated now, and at some unknown time in the future, Adobe is expected to remove Save for Web (Legacy) from Photoshop.

    S
    shoeshine stan작성자
    Participant
    May 16, 2020

    Thanks for the info Conrad_C.

    I have CS5 and I think the "Export As" function is not available in this version. But I know now there's a better way than "Save for web" out there 🙂

    Cheers,
    Stan

    D Fosse
    Community Expert
    D FosseCommunity Expert
    Community Expert
    May 11, 2020

    The jpeg file format uses very agressive data compression to reduce file size on disk. The jpeg compression will shrink a file down to 1 - 10% of original size.

     

    When the file is opened into any image editor, the file is decompressed, and so it increases massively in size. At that point it doesn't even have a file format. It's just an open image like any other open image, whatever file format it was stored as.

     

    It is important to understand that a file format is a storage container. It doesn't apply when the file is open.

     

    Jpeg compression is destructive, non-reversible and cumulative. It should never be used as a working format, only as a one-off end product, not to be touched again.

      S
      shoeshine stan작성자
      Participant
      May 15, 2020

      w

      JJMack
      Community Expert
      JJMackCommunity Expert
      Community Expert
      May 11, 2020

      Firstly Photoshop is not a file editor its a image document editor. Photoshop shows image size not file size they can be very different in size.  Small jpeg files can contain huge images Jpeg files formats uses data compression and can save images into small file at low image quality.  Save for web is used to save small images that are used in web pages. You are being told by save for web that your image's canvas size is too large for web application.

       

      Take a look at you documents canvas size in pixels.

       

      On Windows 10 PS 21.1.1  any canvas size over 8192 pixels width or height save for web  want to downsize to 8192.

       

      JJMack
        약관 및 조건Accessibility statement
        Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices