Can Sigil have an ePub with multiple covers?
 

I'm about to finish a book conversion by hand from PDF to ePub. Now is it possible to embed multiple covers say one for a high res reader like a laptop or something the size of Kindle DX, say a normal cover for regular 800x600 devices and something small for a thumbnail when the case?

Otherwise is it possible to embed a ready made thumbnail of the cover something like in Open Office Writer files?

Thumbnails are auto generated on a per device basis in a device specific manner. The cover specified in the book is typically used to generate the cover. I say typically because not all devices are very good with covers. All you need to do is use the high quality image as the cover and the device will resize and create thumbnails as it feels appropriate.

Thanks. I'll go for a higher resolution than and let each reader do the rest.