Image conversion changed btwn 6.14.1 and 7.12.0

[jdg-calibre]

I apologize in advance if I have simply missed the release note item that calls this out, but I needed to downgrade to 6.14.1 from 7.12.0 today because Apple told me that my image files in the generated ePub were too big.

Example: image1:
7.12.0: 4.49 Mb 2664 x 2991
6.14.1: 99.4 Kb 749 x 842

I first tried use the lossless approach and manipulate the ePub from the Calibre tools menu, but the overall dimensions of the image was still too big, even though the size of the image files was reduced.

So I opted to downgrade to 6.14.1 and that solved the problem.

So I would like to know if there is a specific configuration change that I can make in newer versions, specifically 7.12.0 at the moment, which will perform the same image conversion that I am used to seeing in version 6.14.1.

The source document is a docx in both cases and I was able to test on both Windows 10 and Windows 11 to know that this is not an OS issue. In both cases the MS Word document is configured to preserve images at 220 dpi and the source file is the same in both cases, just to be clear.

For now I have "solved" my issue, but I would like to know that at some point I will be able to upgrade to newer versions of Calibre.

Thank you for your help and insights!

[Quoth]

This is something that should be fixed in your source. In over 10 years I've never had to have Calibre change images, or had an an image issue with Amazon, Apple, Barnes&Noble, Kobo, Google Playbooks, Smashwords etc.

Note that MS Word tools are only affecting appearance for paper/PDF. Fix images outside Word or LO Writer. (Any decent editing program, but not any MS product or tool).


2664 x 2991 is a crazy size for an ebook.

[kovidgoyal]

Look under the EPUB Output section of the conversion dialog.

[BetterRed]

Originally Posted by jdg-calibre

. . .

Thank you for your help and insights!

I make it a practice to resize, resample, compress image files destined for embedding before I insert them in the DOCX, EPUB, PDF… whatever. If that means having different versions of the same images then so be it; my asset management practices take care of that.

Check this setting in calibre:



If it is set as shown, calibre leaves images alone, and Word will do the same if you have its Advanced Options set like this:



I do all I can to avoid Apple products. They do too many things just because…

BR

[Quoth]

^^^ What BetterRead writes!

[jdg-calibre]

Originally Posted by kovidgoyal

Look under the EPUB Output section of the conversion dialog.

Hi Covid,

I did look at the EPUB output section of the Conversion workflow, but I do not see something that is obvious to make the image changes that used to happen without me taking any actions other than to convert the docx to epub.

Did you make changes to Calibre between 6.14.1 and 7.x that affected the way images are processed in a docx file during the conversion to epub?

Many thanks again for you insight and intimate knowledge of the tool!

Jonathan

[DNSB]

Originally Posted by jdg-calibre

I did look at the EPUB output section of the Conversion workflow, but I do not see something that is obvious to make the image changes that used to happen without me taking any actions other than to convert the docx to epub.

Did you try making a change to Shrink images larger than: in the EPUB output options? That would appear to be close to what you wanted. See attached image.

[JSWolf]

Originally Posted by jdg-calibre

I apologize in advance if I have simply missed the release note item that calls this out, but I needed to downgrade to 6.14.1 from 7.12.0 today because Apple told me that my image files in the generated ePub were too big.

Example: image1:
7.12.0: 4.49 Mb 2664 x 2991
6.14.1: 99.4 Kb 749 x 842

I first tried use the lossless approach and manipulate the ePub from the Calibre tools menu, but the overall dimensions of the image was still too big, even though the size of the image files was reduced.

So I opted to downgrade to 6.14.1 and that solved the problem.

So I would like to know if there is a specific configuration change that I can make in newer versions, specifically 7.12.0 at the moment, which will perform the same image conversion that I am used to seeing in version 6.14.1.

The source document is a docx in both cases and I was able to test on both Windows 10 and Windows 11 to know that this is not an OS issue. In both cases the MS Word document is configured to preserve images at 220 dpi and the source file is the same in both cases, just to be clear.

For now I have "solved" my issue, but I would like to know that at some point I will be able to upgrade to newer versions of Calibre.

Thank you for your help and insights!

I use calibre's editor to resize (small if too large) and recompress the cover as I want. You can do the same thing and have your images be the correct size.

[jdg-calibre]

Originally Posted by jdg-calibre

Hi Covid,

I did look at the EPUB output section of the Conversion workflow, but I do not see something that is obvious to make the image changes that used to happen without me taking any actions other than to convert the docx to epub.

Did you make changes to Calibre between 6.14.1 and 7.x that affected the way images are processed in a docx file during the conversion to epub?

Many thanks again for you insight and intimate knowledge of the tool!

Jonathan

I wanted to provide an update. I have solved the problem. I compared the images that were generated using version 6.14.1 and then used the largest image dimensions as the "Shrink images larger than:" factor when using 7.12.0 for each of the platforms that I care about. I was able to get more or less the exact same sizes though there were some minor variations in the generated images despite the guidance. Here are my notes from that test:
======================
Starting with 6.14.1:

Apple: 749x842 for Map of England, 749x694 for Scandinavia and Gotland and the trip of 749x842. Runes are 113x113 as they should be...

B&N: 576x648 and 576x534 and runes are 113x113

Kobo: 512x576 and 512x474 and runes are 113x113

Now, upgrade to 7.12.0 and try to generate with the correct shrinkage for each platform:

Apple: using sizes from 6141: 749x842, get 749x842 and 749x693 (odd) and runes and dingbats are correct.

B&N: using sizes from 6141: 576x648, get 576x646 (odd) and 576x533 (odd) and runes and dingbats are correct...so there is some minor difference on Nook

Kobo: using sizes from 6141: 512x576, get as expected, 512x576 for the Map of England, 512x474 for others and runes and dingbat are correct at 113x113 and 150x28.
======================

Notice the minor differences in the height of the reduced images on Apple and Kobo for some of the images. Again these are minor size issues and must be related to the algorithms used in Calibre I believe since the source images were the same exact dimensions in the MS Word source documents.

So I think I am all set to use 7.12.0 and later with the shrink factors I was able to determine based on 6.14.1 output.

If anyone has any further suggestions or if there is in fact something that Covid might want to review and tweak that would be much appreciated.

Thank you to everyone who already contributed to this thread.

[DNSB]

Just BTW, his name is Kovid Goyal not Covid.

[Quoth]

Originally Posted by jdg-calibre

I wanted to provide an update. I have solved the problem.




I believe since the source images were the same exact dimensions in the MS Word source documents.

No, your problem is that you are not using an image editor to resize images for MS Word.

Then later some would have the CSS edited to a percent width and height: auto;

Calibre is the wrong tool to actually resize images when you have the source.

[Quoth]

Originally Posted by DNSB

Just BTW, his name is Kovid Goyal not Covid.

My corvids also have bone to pick the WHO naming. It's Corvids Press, not Covids Press. The ’ is left out for stylistic reasons. I hope Lynne Truss doesn't appear at the door with what might look like a jar of tadpoles.

See “Eats Shoots and Leaves”.

[BetterRed]

Originally Posted by Quoth

My corvids also have bone to pick the WHO naming. It's Corvids Press, not Covids Press. The ’ is left out for stylistic reasons. I hope Lynne Truss doesn't appear at the door with what might look like a jar of tadpoles.

See “Eats Shoots and Leaves”.

How about if Liz Truss appeared with a packet of tax cuts.

BR

[jdg-calibre]

Originally Posted by DNSB

Just BTW, his name is Kovid Goyal not Covid.

I am completely embarrassed and abashed. It must have been the hour that I was posting. I really should have known better.

My sincere apologies to Kovid.

Thank you David for pointing this out.

[jdg-calibre]

Originally Posted by Quoth

No, your problem is that you are not using an image editor to resize images for MS Word.

Then later some would have the CSS edited to a percent width and height: auto;

Calibre is the wrong tool to actually resize images when you have the source.

Would you then suggest that the images should be resized in a tool like Photoshop and the dimensions that I would want to resize them to be the same dimensions that I have found are needed/acceptable for each of the platforms I am targeting? That is to use the dimensions I mentioned in my last post for each of the images, e.g. :

Apple: 749x842 for Map of England
B&N: 576x648 for Map of England
Kobo: 512x576 for Map of England

These are clearly what are required. And again these are based on the output that I was getting from Calibre 6.14.1 and which produce an output that looks good on the specified platforms.

I certainly can do this, but I am wondering what is wrong with the output of the images from Calibre. What is wrong with the reduced images output from Calibre?