Why are my book covers sometimes so small? - Page 3

theducks · 10-26-2019, 11:10 AM

Quote:

Originally Posted by JSWolf

So if you have a widescreen TV, you'd stretch 4:3 aspect programs to fit and look awful?

That is almost as bad as Pan and Scan(ing) Movies.

I was an very early adopter of Laserdisc for 2 reasons: SOUND quality and Letterbox (on a 4:3 display of the time) and higher line resolution (not line count)

I borrowed a friends VHS version of ET while waiting for the LD to be released. The hole opening (key jingle...) scene lost a whole lot by being P&S'd

LivresInOz · 09-10-2021, 11:01 AM

Additional info that will save people problems:

* Even after you edit the cover html page**, sometimes you may need to restart Kobo for a cover to appear.

* Also, if the device is getting full, it wont show quite a few covers.

__________________________________________
** ie adding the bit in bold

<image width="1027" height="1499" xlink:href="cover.jpeg" style="height:100%; text-align:center;"/>

davidfor · 09-11-2021, 10:27 AM

Quote:

Originally Posted by zenji

Additional info that will save people problems:

* Even after you edit the cover html page**, sometimes you may need to restart Kobo for a cover to appear.

The device only generates the cover for a new book or when there are no stored covers. If you are using calibre to resend a book, it will remove the current cover images. If you don't see the updated cover when you eject the device, it is because it is cached somewhere. Once it drops out of the cache, the updated version will be used.

Quote:

* Also, if the device is getting full, it wont show quite a few covers.

That was a problem a long time ago. Though it was as more to do with the number of books than the space taken. But, you would probably need less than a couple of MB free for it to be a problem now.

LivresInOz · 09-19-2021, 03:13 PM

Quote:

Originally Posted by davidfor

That was a problem a long time ago. Though it was as more to do with the number of books than the space taken. But, you would probably need less than a couple of MB free for it to be a problem now.

Lol that was me a few weeks ago!
I do like to have a lot of choice of books to read...ALOT !

LivresInOz · 09-19-2021, 03:13 PM

Converting to epub in Calibre also solves the problem sometimes, it seems

DNSB · 09-19-2021, 04:42 PM

Quote:

Originally Posted by zenji

Converting to epub in Calibre also solves the problem sometimes, it seems

That would generally indicate that the cover is not properly identified in the epub metadata.

That is why part of my workflow when importing a new book is to open it with Sigil and run various checks on the epub. You can also use calibre's editor which has it's builtin bug checker and the epubcheck addon. I prefer epubcheck since that matches what many publisher use to check ebooks.

davidfor · 09-20-2021, 02:05 AM

Quote:

Originally Posted by zenji

Lol that was me a few weeks ago!
I do like to have a lot of choice of books to read...ALOT !

No it wasn't. As I was directly quoting your statement, and was responding less than 24 hours later, so why would I be referring to that as "ages ago"? I was referring to problems with older firmware. Specifically before version 2.9 of the firmware.

There is a possibility the recent firmware will stop generating cover images when the device only has about about 100MiB free. But, I'm fairly sure it keeps generating them until the device is full. Or within a very few MiBs of full. Are you saying your experience is different? And at how little space free did it happen? It's been a while since I did any experiments with filling the storage on one of my devices. But, I don't remember any issues with cover images. And honestly, it would be the least of my worries about what could happen.

koboy · 09-20-2021, 10:50 AM

Quote:

Originally Posted by davidfor

No it wasn't. As I was directly quoting your statement, and was responding less than 24 hours later, so why would I be referring to that as "ages ago"? I was referring to problems with older firmware. Specifically before version 2.9 of the firmware.

There is a possibility the recent firmware will stop generating cover images when the device only has about about 100MiB free. But, I'm fairly sure it keeps generating them until the device is full. Or within a very few MiBs of full. Are you saying your experience is different? And at how little space free did it happen? It's been a while since I did any experiments with filling the storage on one of my devices. But, I don't remember any issues with cover images. And honestly, it would be the least of my worries about what could happen.

cover images for recently added books not showing if there is less than 100MB free space is a long standing problem in the firmware. i first noticed it using firmware 3.16.0 i'm now using firmware 4.25.15875 and it's still the same. the solution is simple delete some books to take the free space over 100MB and the covers of the books that have just been added will magically appear.

best wishes koboy

Calenorn · 09-20-2021, 10:59 AM

I have a vague memory that cover images that were too small (pixel-wise) would would result in one of those thumbnails with a quarter-sized cover image in the upper right corner. Does that still happen to Kobos? If so, what is the minimum pixel-size for an image that will generate a full-sized cover thumbnail?

JSWolf · 09-20-2021, 11:34 AM

It could be the use of low-res covers on a high-res eInk screen.

Joliet Jake · 09-20-2021, 09:00 PM

I've "solved the problem" for my own Calibre/Kobo. I noted down the title of every book on my e-reader that had a small cover, deleted them from the Kobo, then used Polish Books. (I also used trim a lot.) Then I retransferred all those books to my Kobo.

Polish doesn't change the cover size (there's a plug-in for that) but it does force the first page to "become" the cover, and the first page always has a full sized image. I've not noticed any blurriness either.

davidfor · 09-20-2021, 09:57 PM

Quote:

Originally Posted by Calenorn

I have a vague memory that cover images that were too small (pixel-wise) would would result in one of those thumbnails with a quarter-sized cover image in the upper right corner. Does that still happen to Kobos? If so, what is the minimum pixel-size for an image that will generate a full-sized cover thumbnail?

Yes it still happens. And it happens because that is what the book tells the device to do. For epubs, Kobo renders the start of the book and uses what should be the first page as the cover. If the first page is a small image stuck in one corner, than that is what will be used. As far as the device is concerned, this is how it is supposed to be. And I have a few books where the first page is an image with the title and author in text.

Just using the cover image in the epub is a problem for a couple of reasons. One is they aren't always marked correctly. The other is that if the epub has DRM, then the image is encrypted. I do not believe it is possible for them to get the unencrypted version.

Timboli · 04-30-2025, 09:32 AM

This is obviously an old thread, but still quite relevant.

I still get cover issues with side loaded ebooks, no matter the source. It is I believe, due to a flaw in the Kobo software, that goes beyond side loaded ebooks.

I experience three cover issues with my Kobo device.

(1) Side loaded ebooks, where the cover images have been changed to gray scale (black & white) and small image within a large image, despite the epub file having a decent size color cover image embedded.

(2) Ebooks with less than the three different size cover images.

(3) Ebooks without any cover images stored at all.

Those first two issues are relatively easy to solve, except you have to know where the images are stored for each ebook. The images are stored inside a two number folder structure hierarchy (i.e. .kobo-images\36\120). Some ebooks will share the same folder structure, but most don't, and have folders uniquely theirs. So discovery takes some effort, but once discovered, you can copy the correct size image files to those folders, including over-writing any existing ones, if you wish.

The third issue, is much harder, because you need to know what formula is used to determine those two number folders, because those folders are usually missing on your device, and so you need to create them first, before copying your image files to them.

For all three issues, you need to know the three correct file names. Existing ones makes that easy enough, but for the third issue, you need to check the KoboReader.sqlite file for each specific ebook.

You can of course, just use calibre to do it all for you. I prefer not to, so designed my own helper program, Kobo Cover Fixer, to do all that is required, which took a while to complete, because of that tricky formula. I did eventually think to investigate calibre Python files, and eventually found the right one. And then, because I don't like using Python, especially when sharing things, I converted a cutback version of the relevant portion in the script to a compiled EXE file.

That worked well enough, but I didn't like all the dependencies, so tried to convert to the AutoIt programming language that I use. My first attempt, around 10 months ago, leveraging the use of ChatGPT failed. I tried again more recently, and both ChatGPT and I went real deep, and we eventually succeeded.

I recently fixed all the cover image issues on my Kobo device. That was for over 400 ebooks on my Kobo device (out of over 700).

Anyway, I just wanted to post so some folks could get a heads up. There is a much longer story to all this, but I won't go into that right now.

I will say though, that after fixing all the images, my Kobo actually surprised the hell out of me, by completing a sync, for the first time in many months, probably over a year. That indicates to me, a definite bug in the Kobo device code, which was getting trapped in a never ending Sync loop.

Sirtel · 04-30-2025, 09:42 AM

Never have had any cover issues on my Kobos, and I have couple thousand books on them. Of course, I use calibre.

JSWolf · 04-30-2025, 10:44 AM

I too use calibre and it handles the cover images.

04-30-2025, 09:32 AM	#43
Timboli Sharpest Tool On Shelf Posts: 661 Karma: 2587836 Join Date: Feb 2009 Location: Downunda Device: Kindles, Kobo & Samsung Tablet	This is obviously an old thread, but still quite relevant. I still get cover issues with side loaded ebooks, no matter the source. It is I believe, due to a flaw in the Kobo software, that goes beyond side loaded ebooks. I experience three cover issues with my Kobo device. (1) Side loaded ebooks, where the cover images have been changed to gray scale (black & white) and small image within a large image, despite the epub file having a decent size color cover image embedded. (2) Ebooks with less than the three different size cover images. (3) Ebooks without any cover images stored at all. Those first two issues are relatively easy to solve, except you have to know where the images are stored for each ebook. The images are stored inside a two number folder structure hierarchy (i.e. .kobo-images\36\120). Some ebooks will share the same folder structure, but most don't, and have folders uniquely theirs. So discovery takes some effort, but once discovered, you can copy the correct size image files to those folders, including over-writing any existing ones, if you wish. The third issue, is much harder, because you need to know what formula is used to determine those two number folders, because those folders are usually missing on your device, and so you need to create them first, before copying your image files to them. For all three issues, you need to know the three correct file names. Existing ones makes that easy enough, but for the third issue, you need to check the KoboReader.sqlite file for each specific ebook. You can of course, just use calibre to do it all for you. I prefer not to, so designed my own helper program, Kobo Cover Fixer, to do all that is required, which took a while to complete, because of that tricky formula. I did eventually think to investigate calibre Python files, and eventually found the right one. And then, because I don't like using Python, especially when sharing things, I converted a cutback version of the relevant portion in the script to a compiled EXE file. That worked well enough, but I didn't like all the dependencies, so tried to convert to the AutoIt programming language that I use. My first attempt, around 10 months ago, leveraging the use of ChatGPT failed. I tried again more recently, and both ChatGPT and I went real deep, and we eventually succeeded. I recently fixed all the cover image issues on my Kobo device. That was for over 400 ebooks on my Kobo device (out of over 700). Anyway, I just wanted to post so some folks could get a heads up. There is a much longer story to all this, but I won't go into that right now. I will say though, that after fixing all the images, my Kobo actually surprised the hell out of me, by completing a sync, for the first time in many months, probably over a year. That indicates to me, a definite bug in the Kobo device code, which was getting trapped in a never ending Sync loop. Last edited by Timboli; 04-30-2025 at 09:39 AM.

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09-10-2021, 11:01 AM	#32
LivresInOz LivresInOz Posts: 330 Karma: 15958 Join Date: May 2010 Device: Kobo: Forma + Libra\|Galaxy: TAB A7 + Note 8 tablet\|Boox: Note Air 2	Additional info that will save people problems: * Even after you edit the cover html page*, sometimes you may need to restart Kobo for a cover to appear. Also, if the device is getting full, it wont show quite a few covers. __________________________________________ ie adding the bit in bold <image width="1027" height="1499" xlink:href="cover.jpeg" style="height:100%; text-align:center;"**/>

09-19-2021, 03:13 PM	#35
LivresInOz LivresInOz Posts: 330 Karma: 15958 Join Date: May 2010 Device: Kobo: Forma + Libra\|Galaxy: TAB A7 + Note 8 tablet\|Boox: Note Air 2	Converting to epub in Calibre also solves the problem sometimes, it seems

09-20-2021, 10:59 AM	#39
Calenorn Brash Fumbler Posts: 1,203 Karma: 9224939 Join Date: May 2013 Device: NST, Kobo Mini	I have a vague memory that cover images that were too small (pixel-wise) would would result in one of those thumbnails with a quarter-sized cover image in the upper right corner. Does that still happen to Kobos? If so, what is the minimum pixel-size for an image that will generate a full-sized cover thumbnail?

09-20-2021, 11:34 AM	#40
JSWolf Resident Curmudgeon Posts: 79,771 Karma: 145864619 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	It could be the use of low-res covers on a high-res eInk screen.

09-20-2021, 09:00 PM	#41
Joliet Jake Zealot Posts: 111 Karma: 3098438 Join Date: Feb 2021 Location: Canada Device: Kobo Sage	I've "solved the problem" for my own Calibre/Kobo. I noted down the title of every book on my e-reader that had a small cover, deleted them from the Kobo, then used Polish Books. (I also used trim a lot.) Then I retransferred all those books to my Kobo. Polish doesn't change the cover size (there's a plug-in for that) but it does force the first page to "become" the cover, and the first page always has a full sized image. I've not noticed any blurriness either.

04-30-2025, 09:42 AM	#44
Sirtel Grand Sorcerer Posts: 13,484 Karma: 239219543 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	Never have had any cover issues on my Kobos, and I have couple thousand books on them. Of course, I use calibre.

04-30-2025, 10:44 AM	#45
JSWolf Resident Curmudgeon Posts: 79,771 Karma: 145864619 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	I too use calibre and it handles the cover images.