In truth, there was no real need to actually add so much background detail when considering the traditional story as it is. But this artist simply could not resist - after all Albrecht Altdorfer is still considered to have been the very first modern landscape artist and so his passion for this genre could never be questioned. It was as if he could not help himself but to include features of the Bavarian countryside within his paintings, whichever the chosen theme of the piece.
Susanna herself is visible in the bottom left of the composition along with several maids. The artist then makes use of a tall tree to frame the overall scene from the left hand side which he frequently did in his vertically designed landscape paintings (let so in his drawings that tended to be horizontal instead). It is clear that the artist chose not to allow her to dominate this painting in anyway, she almost appears to be more of an afterthought in order to provide a specific topic of content amidst the overall composition.
The artist puts an unusually large amount of detail into the building work plus also its perspective which dominates this work. In the background he constructs a bright sky scene that helps to make the building itself stand out even more. As a reasonably large painting, those lucky enough to view the original will be able to appreciate the architectural detail more closely.