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<section id="module-imghdr">
<span id="imghdr-determine-the-type-of-an-image"></span><h1><a class="reference internal" href="#module-imghdr" title="imghdr: Determine the type of image contained in a file or byte stream. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">imghdr</span></code></a> — Determine the type of an image<a class="headerlink" href="#module-imghdr" title="Permalink to this headline">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/imghdr.py">Lib/imghdr.py</a></p>
<div class="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.11: </span>The <a class="reference internal" href="#module-imghdr" title="imghdr: Determine the type of image contained in a file or byte stream. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">imghdr</span></code></a> module is deprecated
(see <span class="target" id="index-0"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0594#imghdr"><strong>PEP 594</strong></a> for details and alternatives).</p>
</div>
<hr class="docutils" />
<p>The <a class="reference internal" href="#module-imghdr" title="imghdr: Determine the type of image contained in a file or byte stream. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">imghdr</span></code></a> module determines the type of image contained in a file or
byte stream.</p>
<p>The <a class="reference internal" href="#module-imghdr" title="imghdr: Determine the type of image contained in a file or byte stream. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">imghdr</span></code></a> module defines the following function:</p>
<dl class="py function">
<dt class="sig sig-object py" id="imghdr.what">
<span class="sig-prename descclassname"><span class="pre">imghdr.</span></span><span class="sig-name descname"><span class="pre">what</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">file</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">h</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#imghdr.what" title="Permalink to this definition">¶</a></dt>
<dd><p>Tests the image data contained in the file named by <em>file</em>, and returns a
string describing the image type. If optional <em>h</em> is provided, the <em>file</em>
argument is ignored and <em>h</em> is assumed to contain the byte stream to test.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
</div>
</dd></dl>
<p>The following image types are recognized, as listed below with the return value
from <a class="reference internal" href="#imghdr.what" title="imghdr.what"><code class="xref py py-func docutils literal notranslate"><span class="pre">what()</span></code></a>:</p>
<table class="docutils align-default">
<colgroup>
<col style="width: 26%" />
<col style="width: 74%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head"><p>Value</p></th>
<th class="head"><p>Image format</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'rgb'</span></code></p></td>
<td><p>SGI ImgLib Files</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'gif'</span></code></p></td>
<td><p>GIF 87a and 89a Files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'pbm'</span></code></p></td>
<td><p>Portable Bitmap Files</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'pgm'</span></code></p></td>
<td><p>Portable Graymap Files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'ppm'</span></code></p></td>
<td><p>Portable Pixmap Files</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'tiff'</span></code></p></td>
<td><p>TIFF Files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'rast'</span></code></p></td>
<td><p>Sun Raster Files</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'xbm'</span></code></p></td>
<td><p>X Bitmap Files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'jpeg'</span></code></p></td>
<td><p>JPEG data in JFIF or Exif formats</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'bmp'</span></code></p></td>
<td><p>BMP files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'png'</span></code></p></td>
<td><p>Portable Network Graphics</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'webp'</span></code></p></td>
<td><p>WebP files</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'exr'</span></code></p></td>
<td><p>OpenEXR Files</p></td>
</tr>
</tbody>
</table>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.5: </span>The <em>exr</em> and <em>webp</em> formats were added.</p>
</div>
<p>You can extend the list of file types <a class="reference internal" href="#module-imghdr" title="imghdr: Determine the type of image contained in a file or byte stream. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">imghdr</span></code></a> can recognize by appending
to this variable:</p>
<dl class="py data">
<dt class="sig sig-object py" id="imghdr.tests">
<span class="sig-prename descclassname"><span class="pre">imghdr.</span></span><span class="sig-name descname"><span class="pre">tests</span></span><a class="headerlink" href="#imghdr.tests" title="Permalink to this definition">¶</a></dt>
<dd><p>A list of functions performing the individual tests. Each function takes two
arguments: the byte-stream and an open file-like object. When <a class="reference internal" href="#imghdr.what" title="imghdr.what"><code class="xref py py-func docutils literal notranslate"><span class="pre">what()</span></code></a> is
called with a byte-stream, the file-like object will be <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
<p>The test function should return a string describing the image type if the test
succeeded, or <code class="docutils literal notranslate"><span class="pre">None</span></code> if it failed.</p>
</dd></dl>
<p>Example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">imghdr</span>
<span class="gp">>>> </span><span class="n">imghdr</span><span class="o">.</span><span class="n">what</span><span class="p">(</span><span class="s1">'bass.gif'</span><span class="p">)</span>
<span class="go">'gif'</span>
</pre></div>
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