Glad to be of service, and I understand *exactly* what you mean about preferring a paper reference book. Google Image Search has its uses, but for modeling, it's simply no substitute for a good book.
I was going to recommend the Osprey series, as I've found them to be helpful, though most of their color material will be illustrations. I have found Wade Krawczyk's "German Army Uniforms of World War III" to be helpful since it's all photos of real models wearing a mix of original & reproduction gear (though this book can be skipped if one is not inclined to include figures with one's models.)
George Forty and Thomas L. Jentz have both written extensive works on German armor with excellent photo reference, some of which is difficult/impossible to find elsewhere. Dennis Oliver has a really nice series focusing mainly on German armor, and his books include a section purely about models of the subject, the companies that make those models (Academy, Dragon, Tamiya, etc) as well as companies that produce replacements and accessories like track and photo etch sets.
The Tiger B is my favorite WWII tank, so I've got some books on that in particular. It's not cheap, but Waldemar Trojka's book on the King Tiger is gigantic, and probably the most helpful book I've read on the subject. It cost a pretty penny to ship it from the publisher in Poland, but it was 11/10 worth it for me.
If you find yourself in need of some more esoteric information, like for example, how the Tiger I's radio set is wired, small publishers/distributors like For the Historian have book lines that can be helpful. In this case, they released an English translation of the Tigerfibel - the manual given to Tiger crews during the war. It's amazingly well-written, such that even a poorly-educated draftee or a nerd 70+ years later can make easy sense of it.
My last recommendation is Yoh Morinaga's "Panzertales." Made to accompany a line of 1/144 models for the World Tank Museum in Japan, English translations are tricky to come by, but well worth the wait. It's not especially helpful as a model reference, but the illustrations are in a really cool comic style, and it's loaded with information about what it might have been like to actually fight in the tanks. It also doesn't take itself too seriously, which can be a breath of fresh air.