During my morning reading, I came across an io9 piece by Lauren Davis, "These Medieval-Style Tolkien Illustrations Are Like Nothing We've Ever Seen." In it, Davis reports on and reproduces the Lord of the Rings artwork of Ukrainian artist Sergei Iukhimov, commenting on its resemblance to medieval iconographic traditions. Her comment about jealousy of those who grew up with such editions is likely to be agreed with by a number of her readers, for she is correct in noting that the illustrations do much to capture the feeling of Middle-earth.
How what Davis reports interacts with what Popova discusses (noted in this blog on 17 June 2014) is interesting. Admittedly, Davis can go into more detail with her single artist than Popova can with several, but what is notable is that the medieval scholar Tolkien does not deploy a medieval iconographic style in his illustrations, nor do the others Popova discusses, while Iukhimov does (and more than just the Orthodox style Davis names in discussing him). The effect of Iukhimov, then, is one that does far more to evoke the "medievalness" than do many of the other illustrations under discussion, which is not a condemnation of the illustration quality but is a comment on pseudo-historical context and its interaction with the narrative. There is something of the Crusades in the battles of Gondor and Mordor and much of the broader European medieval, and so the Iukhimov illustrations seem to be more in line with Tolkien's text than even the author's own; they look more like what is found in old manuscript copies, and so they fit more closely with the imagined transmission history of the text that the text itself presents.* Their inclusion makes the text more authentic, both to itself and to the medieval material from which it borrows so much.
*Mary R. Bowman discusses the issue of textual self-transmission in "The Story Was Already Written: Narrative Theory in The Lord of the Rings" (Narrative 14.3 [October 2006]: 272-93), as does Vladimir Brljak in "The Books of Lost Tales: Tolkien as Metafictionist" (Tolkien Studies 7 : 1-34.)