Witness My Fury: Hitler had a strange blonde fetish for a black haired dude me thinks
Artists depicting the Christ child as blonde is not unusual. There are many paintings that do so - the Christ child was often painted with blonde hair - Hitler's painting was only following an established tradition.
Giovanni: Madonna With Doves:
(Mary's robe is blue in the actual painting)
Giovanni: Angel With Madonna
Xanthippie: It's traditional to paint the madonna's dress in blue FMF.
Historically, blue was a rare and expensive pigment and, unlike other colors readily available for the artists' palette, blue was reserved for royalty or people of wealth. Therefore, blue pigment came to be associated with the sacred.
I am curious as well as to why the OP wants to know what other people know about this painting. Obviously, the OP had a purpose for posting it but is reluctant to reveal what that purpose is.