Source 2 is a render. 5.6. 3D Renders or Illustrations as Source:
Using other people's 3D renders or illustrations (even with permission and no matter in which form they are offered) creates a false impression of your artwork. So 3D renders or illustrations can not be used as sources, unless they are entirely created by yourself. Only acceptable non-illustration brushes and clip art may be used, but you need to mention them as a source too. Don't use an image that has been altered by the source owner nor an entire work created by someone else.

Author, somehow I deleted your reply. If you look below the DA image you used, it says "Apophysis and Photoshop." Sometimes DA images can be tricky. The replacement you found works just as well, so good luck!