![generic calibre ebook cover generic calibre ebook cover](https://www.simplehelp.net/images/pdf_to_epub/updated/img02.png)
Therefore my assumption is, that they have no program/library embedded to generate a raster image from SVG files, if they for unknown reasons prefer to use raster images for thumbnails. Presumably Apple will use WebKit to display the content of an EPUB, this has capabilities to display SVG (not so good as for example Opera(Presto), but typically enough to cause no specific problems for simple SVGs). but such improvements should not be relevant for display or conversion or extraction tools, assuming they have no bugs.)
Generic calibre ebook cover software#
Well, the validator should check the SVG file as well, therefore we can assume, that it is technically ok (depending on how this is created, improvements are typically possible - especially if created not with a text editor, but with a program like inkscape etc - I use own scripts and scour to optimise SVGs created by software I did not develop myself. Vector graphics yet - obviously the simplest option would be to extract the SVG cover image itself and use if for the preview without change - this is what I do for my pages with previews of books. If those thumbnails are only raster images, maybe they have not implemented something for If the validator indicates, that the OPF-file is valid, and a viewer produces in general thumbnails from cover images, it is reasonable to contact the developers of the viewer/program to fix this.
![generic calibre ebook cover generic calibre ebook cover](https://www.wired.com/images_blogs/gadgetlab/2010/05/recovery-tool.png)
Readium for WebKit viewers does it as well, the version of azardi I have generates a preview of the SVG cover properly, but does not display the book at all, not a program for practical use obviously. Is 'eBooks' a name of a specific viewer or which viewer do you use? For example current calibre displays a thumbnail. If the book itself remains accessible including the display of the SVG inside the book, the Note that the production of thumbnails for books from cover images is not a task defined or suggested by the ePub format, therefore only an internal problem of each individual viewer. I think, I have one or two, which do not display the book at all, not only the cover image, but the reason can be another as well, I did not test such bugs systematically yet. In several viewers it works as expected, a few others fail obviously for different reasons and in different ways. I use SVG cover images in all of my EPUB3 books.