Early children's adaptations of the Siegfried/Sigurd material often have fantastic pictures. Here are some companions: Sigurd the Dragon Slayer and The Linden Leaf (both 1907, both held in the @britishlibrary). https://twitter.com/whypadraic/status/1358681973464526853
It's also not uncommon for children's adaptations of this material to characterise it as 'an old German story', while discarding half of the Nibelungenlied (Kriemhild's revenge for Siegfried's murder) and building more on material of ultimately Scandinavian origin.
What strikes me as unusual here (I hadn't come across this book before today) is its date: most English-language children's adaptations of this material post-date Wagner's Ring cycle and often draw on it.
1848 – aside from its other significance – is also the date of the first (supposedly) full Nibelungenlied translation, produced by the rather maligned English translator, Jonathan Birch, a friend of Frederick William IV of Prussia.
Like this publication, then, with its German images, Birch's translation was a joint enterprise between Britain and Germany. It was printed (posthumously) in Berlin.
While some English-language versions of this material included specially commissioned images, others included previously published German images. Lydia Hands' children's version (1880) reprinted Julius Schnorr von Carolsfeld's famous woodcuts.
And images transmitted with this material informed the way people thought about it. Schnorr's woodcuts were particularly influential. The first woman to translate/adapt the Nibelungenlied (1877), Auber Forestier (Aubertine Woodward Moore) named them as an inspiration.