oh dear gods dude, thats the ultimate question an the bane of my own existence as well.
Depends on what kind of art book it is.
Is it for your own personal and spontaneous use?
if so, it will get way too confusing trying to separate, that way you can also just carry one with you and enter stuff into it anywhere anytime.
Is it a planned out artbook that you are doing as a work of art? If so, I personally think words and art look well together, compliment eachother. But can also stand alone. I would also recommend bringing them together in this instance but either way is fine.
Personally, I did try to divi up my stuff, and it got a bit confusing both ways. I have one book I carry everywhere for everything (inlcuding some writing), but I also keep a secret writing book for just my poems and stories by my bed, because while im ok with letting everyone browse my art and me showing off... im not as easy going about my words.
it's an art book - poetry is art. To publish it in the same book probably would depend on how relative it is to one another - if it offers a different perspective on the piece (image or word) and all that's been priorly mentioned. From the view of an induvidual I'd say that it'd be preferrable to have complete poems with complete works of art - gives it more dynamics, depth, meaning - but that is simply my personal preferance.