This is the Proof version on the American Buffalo gold bullion coin. Like all US Mint images, this image is in the public domain as a work of the US government.
US government
<p><a rel="nofollow" class="external free" href="https://www.usmint.gov/about_the_mint/CoinLibrary/#BufGoldBull">http://www.usmint.gov/about_the_mint/CoinLibrary/#BufGoldBull</a>
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<ul><li><a href="//commons.wikimedia.org/wiki/File:2006_American_Buffalo_Proof_Obverse.jpg" title="File:2006 American Buffalo Proof Obverse.jpg">File:2006 American Buffalo Proof Obverse.jpg</a></li>
<li><a href="//commons.wikimedia.org/wiki/File:2006_American_Buffalo_Proof_Reverse.jpg" title="File:2006 American Buffalo Proof Reverse.jpg">File:2006 American Buffalo Proof Reverse.jpg</a></li></ul>