When using web viewers, panorama VR or image sequences on a page, these will not be rendered when the Twixl Publisher export creates the thumbnails that are used for the Table of Contents (TOC) overview.
There is a way to customize the thumbnails that are being displayed though…
For InDesign-based content
The thumbnails that you want to customize need to be placed in the same folder as the InDesign files for the article. If you use a publication-based workflow, it is best practice to keep both the different articles and the publication (InDesign book) file within the same folder.
The thumbnail files need to have the same name as the article, but with .jpg as the extension instead of .indd, and have a minimum size of 256x256 pixels (or a larger, preferably square, size).
The retina thumbnails should add a suffix @2x to the file name, e.g. ArticleName@2x.jpg, and have a minimum size of 512x512 pixels (or a larger, preferably square, size).
For articles where no custom thumbnail has been defined, the Twixl Publisher plug-in will generate one on the fly during the Export process.
A sample folder structure should then look as follows:
- Article1.jpg (256 × 256 pixels)
- Article1@2x.jpg (512 × 512 pixels)
- Article2.jpg (256 × 256 pixels)
- Article2@2x.jpg (512 × 512 pixels)
The Twixl Distribution Platform will generate thumbnails. Here are the rules you need to take in account:
- If there is an index.jpg file in the .zip file on the same level as the index.html file, that image will be used as a thumbnail
- If there is an index.jpeg file in the .zip file on the same level as the index.html file, that image will be used as a thumbnail
- If there is an index.png file in the .zip file on the same level as the index.html file, that image will be used as a thumbnail
- If no images are present, the Twixl Distribution Platform will look at the first image it can find in the HTML-file.