Resizing images in bulk?

salty-horse · 01-10-2022, 10:56 AM

Is there a way to resize images in bulk via the editor?

I have an EPUB file with many large "cover" images - I want to resize all of those images, but not others.

ATM, my options appear to be:
1) Export all images, resize, then import.
2) Click each image, then click the resize tool.
3) Convert from EPUB to another format, then back to EPUB, with the preference to resize images.

Am I missing something, or is it not available ATM?

kovidgoyal · 01-10-2022, 11:05 AM

Use the unpack book tool (preferences->toolbars and add it to your main toolbar)

theducks · 01-10-2022, 11:17 AM

or just type 'U'

I used to use the bulk resize feature of Paintshop Pro 4 (dated myself

)
Then you just repack (the tool is still open),

You may need to edit the stylesheet if it also sets sizes

salty-horse · 01-12-2022, 08:53 AM

Hmm, that's similar to my option 1. I managed it, but it still required some work.

Is there a way to run an epub -> epub conversion to make use of that automatic image resize feature?

rjwse@aol.com · 01-12-2022, 09:20 AM

You can 'effectively' resize (1) all, (2) some, or (3) individual images via CSS.

If you put a command in stylesheet.css all of the images will show up at 50%.
img {width: 50% ; float: left ; margin-right: .5em ; }

Alternately, this same command wrapped in <style></style> at the beginning of an html segment will act only on images in that html segment.

Alternately, you can command a single image to be half size by inserting this command inside of the image tag inside of quotes: style="in here"

This does not change the aspect ratio, just the size shown. Nor does it trim the images.

Best regards, Pop

salty-horse · 01-12-2022, 09:32 AM

I don't think CSS "resizing" is relevant here (and requires more work to edit the text files). The issue is the file sizes. My ebook reader refuses to display large images, and works fine when I resize the dimensions of the files. And I'd much rather store a 2MB ebook than a 30MB.

Doitsu · 01-15-2022, 03:54 PM

Have you already tried Polish book > Lossless compress images?

salty-horse · 01-15-2022, 04:04 PM

Compressing the images reduces the size of the large cover images by half, but I suspect they're still too large for my ebook reader (haven't tried).

I still need to resize their dimensions manually.

DNSB · 01-15-2022, 04:11 PM

Have you looked at the Resize Cover plugin? I've used that with ModifyEpub to resize the cover image and then embed it in the epubs in calibre.

salty-horse · 01-15-2022, 04:27 PM

From what I'm reading about that plugin it looks like it only handles the cover image of the ePub.

The ebooks I'm dealing with (Tor.com short story collections) have a "cover image" before each story. It's not a "cover image" as the epub terminology defines it.

Anyway, I completed the process manually for the ebooks I currently have by unpacking, resizing, and repacking the files with the "Unpack book" feature.

01-10-2022, 10:56 AM	#1
salty-horse Wizard Posts: 1,672 Karma: 17163744 Join Date: Sep 2008 Device: Kobo Clara 2E	Resizing images in bulk? Is there a way to resize images in bulk via the editor? I have an EPUB file with many large "cover" images - I want to resize all of those images, but not others. ATM, my options appear to be: 1) Export all images, resize, then import. 2) Click each image, then click the resize tool. 3) Convert from EPUB to another format, then back to EPUB, with the preference to resize images. Am I missing something, or is it not available ATM?

01-12-2022, 09:32 AM	#6
salty-horse Wizard Posts: 1,672 Karma: 17163744 Join Date: Sep 2008 Device: Kobo Clara 2E	I don't think CSS "resizing" is relevant here (and requires more work to edit the text files). The issue is the file sizes. My ebook reader refuses to display large images, and works fine when I resize the dimensions of the files. And I'd much rather store a 2MB ebook than a 30MB. Last edited by salty-horse; 01-12-2022 at 09:35 AM.

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01-10-2022, 11:05 AM	#2
kovidgoyal creator of calibre Posts: 44,380 Karma: 23764838 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Use the unpack book tool (preferences->toolbars and add it to your main toolbar)

01-10-2022, 11:17 AM	#3
theducks Well trained by Cats Posts: 30,392 Karma: 58053698 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	or just type 'U' I used to use the bulk resize feature of Paintshop Pro 4 (dated myself ) Then you just repack (the tool is still open), You may need to edit the stylesheet if it also sets sizes

01-12-2022, 08:53 AM	#4
salty-horse Wizard Posts: 1,672 Karma: 17163744 Join Date: Sep 2008 Device: Kobo Clara 2E	Hmm, that's similar to my option 1. I managed it, but it still required some work. Is there a way to run an epub -> epub conversion to make use of that automatic image resize feature?

01-12-2022, 09:20 AM	#5
rjwse@aol.com Addict Posts: 302 Karma: 2228060 Join Date: Dec 2013 Location: LaVernia, Texas Device: kindle epub readers on android	You can 'effectively' resize (1) all, (2) some, or (3) individual images via CSS. If you put a command in stylesheet.css all of the images will show up at 50%. img {width: 50% ; float: left ; margin-right: .5em ; } Alternately, this same command wrapped in <style></style> at the beginning of an html segment will act only on images in that html segment. Alternately, you can command a single image to be half size by inserting this command inside of the image tag inside of quotes: style="in here" This does not change the aspect ratio, just the size shown. Nor does it trim the images. Best regards, Pop

01-15-2022, 03:54 PM	#7
Doitsu Grand Sorcerer Posts: 5,636 Karma: 23191067 Join Date: Dec 2010 Device: Kindle PW2	Have you already tried Polish book > Lossless compress images?

01-15-2022, 04:04 PM	#8
salty-horse Wizard Posts: 1,672 Karma: 17163744 Join Date: Sep 2008 Device: Kobo Clara 2E	Compressing the images reduces the size of the large cover images by half, but I suspect they're still too large for my ebook reader (haven't tried). I still need to resize their dimensions manually.

01-15-2022, 04:11 PM	#9
DNSB Bibliophagist Posts: 39,686 Karma: 154147704 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	Have you looked at the Resize Cover plugin? I've used that with ModifyEpub to resize the cover image and then embed it in the epubs in calibre.

01-15-2022, 04:27 PM	#10
salty-horse Wizard Posts: 1,672 Karma: 17163744 Join Date: Sep 2008 Device: Kobo Clara 2E	From what I'm reading about that plugin it looks like it only handles the cover image of the ePub. The ebooks I'm dealing with (Tor.com short story collections) have a "cover image" before each story. It's not a "cover image" as the epub terminology defines it. Anyway, I completed the process manually for the ebooks I currently have by unpacking, resizing, and repacking the files with the "Unpack book" feature.

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