Strange image conversion problem ePub to mobi

[AlexBell]

Please bear with me.

Since my last post I did some work on the files, starting with the TFatITest.epub and TFatITest.mobi which I uploaded yesterday and which several people kindly tested and found that the mobi file does show the signature.png image.

All I have done is change the file name, and changed the title in the content.opf file to TFatI so I could keep the previous two files for later testing.

I then uploaded the TFatI.epub file into my calibre library, and converted it to mobi, and then tested the TFatI.mobi file with the calibre viewer and on my Kindle3. The signature.png image is not showing, and there is nothing to show that it was ever there. The image does show in the ebpub file with ADE and the calibre viewer.

Could you please test the TFatI.mobi file? If the signature.png image is showing I'll have to worry whether there is something wrong with my computer, or with my vision.

[dwig]

Originally Posted by AlexBell

Please bear with me....
Could you please test the TFatI.mobi file? If the signature.png image is showing I'll have to worry whether there is something wrong with my computer, or with my vision.

I downloaded both your new EPUB and new MOBI. The MOBI fails to show the sig in both my Kindle Previewer and K3 device though the other image questioned in your original post is fine.

I ran you new EPUB though Calibre 0.8.11 on my machine and the sig displays fine in the resulting MOBI, again in both Previewer and the K3.

MOBI doesn't support PNG so Calibre would have to be doing some conversion on the image data. I suggested using JPEGs instead because PNG is an extremely complex and extensive spec and perhaps your PNGs are a flavor that is somewhat problematic in Calibre's image code. JPEGs have a more limited range of options and less likely to encounter a flaw in conversion.

Whatever is happening, its not a universal bug in the code since conversion on my machine from your new EPUB was fine.

I've attached my EPUB to MOBI conversion

[kovidgoyal]

Converting your epub also results in the images being present in the MOBI for me. It sounds like you have a problem with some conversion setting. Try doing a conversion with all settings at defaults.

[AlexBell]

Thanks to you both. I'll try your suggestions

Well, it's fixed, but I really don't know why or how.

The only things I changed were to make a new png image from the jpg provided by dwig, and to remove the setting to ignore margins - and yes, I know I should have done them separately to get a better idea of what was happening.

My best guess is that telling calibre to ignore the wide margins may have affected this the first image in the book - none of the other images which had exactly the same markup were affected.

It may be that as dwig said the original png was the problem. But I am as sure as I can be that same image worked without problem as I developed and tested the conversion.

Anyway it's fixed. Thanks again for all your help.

[AlexBell]

It's happened again!

Some time ago I was very concerned that an image did not show when converting from ePub to Kindle even though similar images did show. After some discussion it seems that the problem may have been caused by me setting the conversion process to hide fake margins - whatever the reason the image 'came back' and I went on developing the book.

I've recently changed other parts of the ebook, and am using the latest version of calibre, and that same image again does not show in the Kindle file even though though it does show in the original ePub file. Other similar files do show - bigger and smaller, deep color or 255 grays, and different percentages.

The file which does not show is signature.png, which is attached. Also attached are Greenman.png which does show, and SPblurb.png which does show.

All three files have the same markup shown below, except of course that the file names are different, and the widths are different.

<div class="centre">
<img src="images/signature.png" alt="signature"
width="60%" />
</div>

Can anyone explain what I am doing wrong, or what calibre is doing wrong? The image signature.png does show when I generate the Kindle file with the KindlePreviewer.

I have set the calibre setting to default except for the input and output settings, and have used the image dwig provided.

I've removed the signature.png image and replaced it with signature.jpeg from the original source - that is, not from converting the png to jpeg. That doesn't show either.