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  <title>MagickCore, C API: Compute a Message Digest for an Image @ ImageMagick</title>
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<p class="text-center"><a href="signature.php#SignatureImage">SignatureImage</a></p>

<h2><a href="https://imagemagick.org/api/MagickCore/signature_8c.html" id="SignatureImage">SignatureImage</a></h2>

<p>SignatureImage() computes a message digest from an image pixel stream with an implementation of the NIST SHA-256 Message Digest algorithm.  This signature uniquely identifies the image and is convenient for determining if an image has been modified or whether two images are identical.</p>

<p>The format of the SignatureImage method is:</p>

<pre class="text">
MagickBooleanType SignatureImage(Image *image,ExceptionInfo *exception)
</pre>

<p>A description of each parameter follows:</p>

<dd>
</dd>

<dd> </dd>
<dl class="dl-horizontal">
<dt>image</dt>
<dd>the image. </dd>

<dd> </dd>
<dt>exception</dt>
<dd>return any errors or warnings in this structure. </dd>

<dd>  </dd>
</dl>
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