I kind of get the vibe that the artist wanted to 'tie' in the Sauron/Melkor association with cats. I dunno, best guess of mine.
Looking at that face though, I just want to go and hug my feline fluff of fur.
I have to agree though, no one is practicularly going to have an illustration in the same light as Tolkien's, or maybe Alan Lee's (I say his name as well, because he has worked with the Tolkien family for some years now), so some takes on certain events might come off as strange to the rest of us.
Then again, some are just too odd it is more puzzling than humourious.
Personally, I don't think I could ever illustrate Sauron after the fall of Numenor, since Tolkien had his image in such a way that is familiar and very distinct, but particularly hard to encompass beyond the 'great eye' factor. Sometimes words can do the best in our minds for certain things, though it doesn't mean all things illustrated are a 'tainted image' of the original.
Also because, it is quite interesting and fun to make Sauron as this suave and sly advisor, appealing to the wants and wishes of kings.
~ Ka