I have no longer interest in the subject, especially since most of the stuff about it is either written by demonizing researcher, or from sanctifying ones.
I think instead of wasting time with the fringe sides of the subject (that may be interesting on the aestetic/apocalyptic/bizarre field), you should get into the real stuff written by the ideologist themsleves.
So, not so much Himmler's black new age mumbo jumbo, but the writings of the several leaders.
In my opinion you should start from Hitler's Mein Kampf, but also Mein Leben and what in Italian sounds like "ideas on the destiny of the world". There you can read all the ideas that led him to power, understanding Germany's social situation after WWII, his strict antisemitism, etc.
Then you can't miss Goebbles' diaries, the alreay mentioned book by Albert Speer (to be read alongside Gitta sereny's "Speer - at battle with truth", where she debunk many lies he wrote in his biography).
Rosenberg's The myth of the XX Century. A quite frontal attack on Christianity that, anyway, was pure excercise of style, since Catholics and Protestants never had problems (apart from some left-wing pristes internated in Dachau, or the likes of Father Kolbe). It is quite radical also on the racist/antisemitic side.
Then you can get any book from Leon Degrelle who, although being Belgian, can give you a perfect idea of the mentality leading Waffen SS to form the European army for the attempt of invasion in Russia.
Walter Darre's "The new nobility of blood and soil" describes pretty well the whole mystic of the land thing, with strong parts regarding the idea of the warrior/peasant, a bit like a few years before Junger saw the same in the "worker".
A quite critical book on the subject is Julius Evola's "Nazism seen from the right".
Regarding images, get any catalogue from memorial sites and you will find plenty of that.
I own two versions of the Dachau one.
