books size

gianni_fed · 01-28-2019, 04:34 AM

Hello,
sometimes I find books large, 10-20MB but that can be reduced to a few KB because they contain images with very high resolutions while, to read an e-book, 72dpi are enough.
This is the way I have found to reduce the size of all images at once, two freewere programs (FILEminimizer Picture, Bulk Rename Utility and WinRAR 5.20) are needed:
1 - open the book with the right button on the book and Edit book.
2 - select all the images and, with the right key, export all the images ... in the window that opens click on "Select folder" on the bottom right.
3 - open FILEminimizer Picture, check the box "Custom Compression" and click on "Settings", I chose 640x480 and 40%.
In the upper bar click on "Settings", in Settings I have selected "Create new Optimized files, I put" _ "in the" Add this extension to file name "box and then" Insert before file name ".
In Image Settings I selected "Allow editing of the format and I checked the box" Allow image resizing.
4 - open the folder where you saved the images, select all the images and drag them into Fileminimizer Picture, click on Optimize file.
5 - open Bulk Rename Utility, navigate to the folder where the reduced files are located, select them and, in the "Remove" window enter 2 in the "First n" box, then click on "Rename". The program will remove the first two characters from the names of the files.
6 - at this point return to Caliber, in the book details window on the right, right click on: "Path: Click to open" and, again with the right button on the file, click "Open with" and select WinRAR archiver.
usually the images are in the folder "OEBPS" -> Images, select them and with the right key -> Delete files and confirm, always with the right button -> Add files to archive, navigate to the reduced images, select them and date Ok and confirmed. Close WinRAR, close the folder and it's done.
The procedure seems long and laborious but I assure you that it is easy and fast.

Please note, if there are png images in the book that File minimizer does not manage, after point 1, you need to change "png" in "jpg" throughout the book in "Search" -> Find / replace (Ctrl + F) e, after point 2, use a small program like Bulk Image Converter to change all the extensions from png to jpg.

I hope this procedure can help someone.

Gary_M_Mugford · 01-31-2019, 02:39 PM

Gianni,

I usually convert the book to Mobi (I read via a Kindle) and the conversion really takes a lot of the air out of the book, especially if coming in from a Hi-Res infested EPub. You might want to try converting, even mobi to mobi or mobi to EPub and back or whatever you want to try. THEN compare that with the way you've developed. You MIGHT find it easier and within percentage points of what you are doing to just hilite and click convert and OK from within Calibre. Or, your way might be a LOT better and this will result in something good for the community to know.

GM

Brett Merkey · 01-31-2019, 02:54 PM

I may be missing something here. Why not use the super quick and effective tool provided by Calibre to reduce image file size?

In the Editor window, select Tools > Compress Images Losslessly. Checking the "Enable lossy compression" option will reduce them further. I often use a compression quality value of 50.

ilovejedd · 01-31-2019, 03:04 PM

Quote:

Originally Posted by Brett Merkey

I may be missing something here. Why not use the super quick and effective tool provided by Calibre to reduce image file size?

In the Editor window, select Tools > Compress Images Losslessly. Checking the "Enable lossy compression" option will reduce them further. I often use a compression quality value of 50.

Afaik, that only changes compression ratio, not resolution.

theducks · 01-31-2019, 03:25 PM

Quote:

Originally Posted by ilovejedd

Afaik, that only changes compression ratio, not resolution.

That tool also allows you to Resize eg 2048w > 450w (and maintain aspect)

BetterRed · 01-31-2019, 03:50 PM

Quote:

Originally Posted by theducks

That tool also allows you to Resize eg 2048w > 450w (and maintain aspect)

Really, how can you do that ?

Click image for larger version

Name: 1.jpg
Views: 214
Size: 44.7 KB
ID: 169417

BR

Brett Merkey · 01-31-2019, 04:22 PM

Quote:

Afaik, that only changes compression ratio, not resolution.

Changing resolution can be a complex process that may not attain desired results. A 300x300px image at 300ppi will be one inch across in a Paperwhite 3+ but will (without device intervention) take up the entire screen of a 150ppi tablet. What seems to happen is that many devices re-interpret image resolution to best fit the screen.

I am quite happy with altering file size (compression) or pixel dimensions when necessary. These are things Calibre can do, even tho as separate tools in the user interface.

ilovejedd · 01-31-2019, 06:52 PM

Quote:

Originally Posted by Brett Merkey

Changing resolution can be a complex process that may not attain desired results. A 300x300px image at 300ppi will be one inch across in a Paperwhite 3+ but will (without device intervention) take up the entire screen of a 150ppi tablet. What seems to happen is that many devices re-interpret image resolution to best fit the screen.

I am quite happy with altering file size (compression) or pixel dimensions when necessary. These are things Calibre can do, even tho as separate tools in the user interface.

Curious, aside from conversion, how do you change resolution of images inside a book using Calibre (not just cover but other embedded images as well)?

There's only so much that changing compression ratio will do. I have books with 12 megapixel images. For books I deem unreasonably large, I unpack, then use IrfanView to batch resize and convert, overwriting in place (JPEG compression 75%), then repack.

theducks · 01-31-2019, 06:58 PM

Quote:

Originally Posted by BetterRed

Really, how can you do that ?

Attachment 169417

BR

Where is that.
I thought we were talking about the Image tool in the calibre editor?

DNSB · 01-31-2019, 07:11 PM

Quote:

Originally Posted by ilovejedd

Curious, aside from conversion, how do you change resolution of images inside a book using Calibre (not just cover but other embedded images as well)?

Open the book in calibre's editor, select the image and edit away. See attached screenshot.

theducks · 01-31-2019, 07:20 PM

Quote:

Originally Posted by DNSB

Open the book in calibre's editor, select the image and edit away. See attached screenshot.

Yep

That was what I use frequently

ilovejedd · 01-31-2019, 07:45 PM

Quote:

Originally Posted by DNSB

Open the book in calibre's editor, select the image and edit away. See attached screenshot.

Thanks for the tip. I was looking for an option in the menubar.

Just tried it and I think I'll stick to my current method. File manager + IrfanView is easier when I need to preview and process a batch of images.

BetterRed · 01-31-2019, 10:11 PM

Quote:

Originally Posted by Brett Merkey

I may be missing something here. Why not use the super quick and effective tool provided by Calibre to reduce image file size?

In the Editor window, select Tools > Compress Images Losslessly. Checking the "Enable lossy compression" option will reduce them further. I often use a compression quality value of 50.

Quote:

Originally Posted by theducks

That tool also allows you to Resize eg 2048w > 450w (and maintain aspect)

Quote:

Originally Posted by BetterRed

Really, how can you do that ?

Attachment 169417

BR

Quote:

Originally Posted by theducks

Where is that.
I thought we were talking about the Image tool in the calibre editor?

. . .

BR

gianni_fed · 02-03-2019, 06:18 AM

Hi,
In the included image there is a comparison between the two image compression methods: Compress Images Losslessly and the one I use.
Bye,
Gianni

01-28-2019, 04:34 AM	#1
gianni_fed Enthusiast Posts: 28 Karma: 10 Join Date: Oct 2015 Device: none	books size Hello, sometimes I find books large, 10-20MB but that can be reduced to a few KB because they contain images with very high resolutions while, to read an e-book, 72dpi are enough. This is the way I have found to reduce the size of all images at once, two freewere programs (FILEminimizer Picture, Bulk Rename Utility and WinRAR 5.20) are needed: 1 - open the book with the right button on the book and Edit book. 2 - select all the images and, with the right key, export all the images ... in the window that opens click on "Select folder" on the bottom right. 3 - open FILEminimizer Picture, check the box "Custom Compression" and click on "Settings", I chose 640x480 and 40%. In the upper bar click on "Settings", in Settings I have selected "Create new Optimized files, I put" _ "in the" Add this extension to file name "box and then" Insert before file name ". In Image Settings I selected "Allow editing of the format and I checked the box" Allow image resizing. 4 - open the folder where you saved the images, select all the images and drag them into Fileminimizer Picture, click on Optimize file. 5 - open Bulk Rename Utility, navigate to the folder where the reduced files are located, select them and, in the "Remove" window enter 2 in the "First n" box, then click on "Rename". The program will remove the first two characters from the names of the files. 6 - at this point return to Caliber, in the book details window on the right, right click on: "Path: Click to open" and, again with the right button on the file, click "Open with" and select WinRAR archiver. usually the images are in the folder "OEBPS" -> Images, select them and with the right key -> Delete files and confirm, always with the right button -> Add files to archive, navigate to the reduced images, select them and date Ok and confirmed. Close WinRAR, close the folder and it's done. The procedure seems long and laborious but I assure you that it is easy and fast. Please note, if there are png images in the book that File minimizer does not manage, after point 1, you need to change "png" in "jpg" throughout the book in "Search" -> Find / replace (Ctrl + F) e, after point 2, use a small program like Bulk Image Converter to change all the extensions from png to jpg. I hope this procedure can help someone.

02-03-2019, 06:18 AM	#14
gianni_fed Enthusiast Posts: 28 Karma: 10 Join Date: Oct 2015 Device: none	Only to have complete information Hi, In the included image there is a comparison between the two image compression methods: Compress Images Losslessly and the one I use. Bye, Gianni Attached Thumbnails

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01-31-2019, 02:39 PM	#2
Gary_M_Mugford Groupie Posts: 180 Karma: 299 Join Date: Jul 2010 Location: Brampton ON Device: Kobo, Kindle3	Gianni, I usually convert the book to Mobi (I read via a Kindle) and the conversion really takes a lot of the air out of the book, especially if coming in from a Hi-Res infested EPub. You might want to try converting, even mobi to mobi or mobi to EPub and back or whatever you want to try. THEN compare that with the way you've developed. You MIGHT find it easier and within percentage points of what you are doing to just hilite and click convert and OK from within Calibre. Or, your way might be a LOT better and this will result in something good for the community to know. GM

01-31-2019, 02:54 PM	#3
Brett Merkey Not Quite Dead Posts: 195 Karma: 654170 Join Date: Jul 2015 Device: Paperwhite 4; Galaxy Tab	I may be missing something here. Why not use the super quick and effective tool provided by Calibre to reduce image file size? In the Editor window, select Tools > Compress Images Losslessly. Checking the "Enable lossy compression" option will reduce them further. I often use a compression quality value of 50.