There is no "official" Stormbringer image. Michael Moorcock cites the Cawthorn's version as being the closest to his original vision of the sword. Specially this one:
This image has also led to the incorrect idea that Elric is a dark elf, or even an elf. There's a thread about that at multiverse.org.
Walt Simonson's renditions of Stormbringer on the covers of Elric: Making of the Sorcerer are three of the Stormbringer's that Moorcock authorized over the last 40 years, except the fourth which is Simonson's original. Note that Elric is raising Stormbringer higher with each cover. By the way, the artwork within those comics is like nothing I've ever seen before. Also, issue one is awesome. Also note that the Actorios stone is embedded in the handle of the sword. http://www.multiverse.org/imagehive/v/bookcovers/comiccovers/Originals/album29/
The sword that was posted above can be customized. Go to this album to see more photos of the Stormbringer above, and check out the Moorcock authorized scimitar: http://www.multiverse.org/imagehive/v/misc/Stormbringer/
To get an idea what your tattoo might look like, check out the tattoo album here: http://www.multiverse.org/imagehive/v/Artwork/album54/ Here's what Gould's Stormbringer looks like:
Your going to find piles of Stormbringers in the book cover section: http://www.multiverse.org/imagehive/v/bookcovers/books/mikebooks/
This is my personal favorite, cover, Elric and Stormbringer: