I think this non-standard image was chosen by the publishers in part because it is non-standard and pictorially striking, not because it fits closely with any part of
The Silmarillion.
It might be intended to represent Ilúvatar at the moment when He made the universe
real.
See, for example, other slightly similar pictures:
- https://pbs.twimg.com/profile_images...Nahar_Doa.jpeg
- http://fc00.deviantart.net/fs71/i/20..._Nahar_Doa.jpg
- http://fc07.deviantart.net/fs70/i/20..._Nahar_Doa.jpg
- http://paulhectort.deviantart.com/art/Ainur-349449138
- http://www.thefuturetense.net/wp-con...s-2011-web.jpg
- http://tolkiengateway.net/w/images/t..._the_Ainur.jpg
- http://1.bp.blogspot.com/_-lRNi5OaDE...iluvatar-2.jpg
- http://translate.google.ca/translate...ri&prev=search
- http://fc00.deviantart.net/fs71/f/20...ym-d5sbsp3.jpg
- http://enanoakd.deviantart.com/art/E...lace-402141225
- http://www.lamagiaenarda.com/imagene...valar/namo.jpg
The image could represent Fëanor creating the Silmarils, but Fëanor is supposed to look like an Elf, not like some kind of bird humanoid.
Perhaps if you could provide the name of the artist, we might not have to rely so much on guessing. Have you tried getting in touch with the publisher of this edition?