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G
Geobop
Known Participant
September 7, 2022
Answered

Best Image Compression for Resolution 300 Images

  • September 7, 2022
  • 1 reply
  • 680 views

I was told the best strategy for creating high quality images is to set the resolution at 300, then choose the "Save a Copy" command. Since I'm creating images for epubs, most are 1,500-2,000 pixels wide.

 

However, I just discovered that some online vendors won't accept my epubs because the file size is too big. Barnes & Noble has a maximum allowance of 20 MB, while one of my smallest books is 70 MB.

 

So, is there a way to compress images without losing quality, either with Photoshop or another software program or service?

Correct answer Rob_Cullen

"If I take one of my 2,000-pixel-wide 300-resolution jpg's and change the resolution to 72, would that be good enough for an epub?"

Yes it will be, but the "resolution' does not matter whatsoever! PPI could be '1' or '1000' or '300' - It will make NO difference. You will always have a 2000-PIXEL-WIDE image.

 

1 reply

TheDigitalDog
TheDigitalDog
Inspiring
September 7, 2022

What you were told is a fundamental misunderstanding and certainly no rule. 

The pixels you need or someone asks for are what you need to produce. If that is 1,500-2,000 pixels wide, so be it; the resolution tag (300 or otherwise) is meaningless, just a metadata tag. Work in pixels. 

I wrote my first article for a magazine on Resolution way back in 1998 and I see it's still a topic of confusion today. FWIW, the article is archived here:
http://digitaldog.net/files/Resolution.pdf
Will the receiving end accept a TIFF? Lossless compression is possible with caveats:

http://digitaldog.net/files/TIFFvsPSD.pdf

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"
    G
    GeobopAuthor
    Known Participant
    September 7, 2022

    I have to go back and read that article you linked to again. The lady I hired to do the interior design on my book said she wanted all the images as jpg's, measuring 1,500-2,000 pixels wide. I can't remember if she specified a resolution, but I think she said 300.

    To cut to the chase, I should probably ask what kind of images will suffice in an epub. I do have the luxury of converting some of the simpler images to png's and svg's. But what about the jpg's? If I take one of my 2,000-pixel-wide 300-resolution jpg's and change the resolution to 72, would that be good enough for an epub?

     

    Thanks.

    Rob_Cullen
    Community Expert
    Rob_CullenCommunity ExpertCorrect answer
    Community Expert
    September 7, 2022

    "If I take one of my 2,000-pixel-wide 300-resolution jpg's and change the resolution to 72, would that be good enough for an epub?"

    Yes it will be, but the "resolution' does not matter whatsoever! PPI could be '1' or '1000' or '300' - It will make NO difference. You will always have a 2000-PIXEL-WIDE image.

     

    Regards. My System: Windows-11, Lightroom-Classic 15.1.1, Photoshop 27.3.1, ACR 18.1.1, Lightroom 9.0, Lr-iOS 10.4.0, Bridge 16.0.2 .
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