php-doc-en/reference/image/functions/getimagesize.xml

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 <refentry id="function.getimagesize">
  <refnamediv>
   <refname>getimagesize</refname>
   <refpurpose>Get the size of an image</refpurpose>
  </refnamediv>
  <refsect1>
   <title>Description</title>
    <methodsynopsis>
     <type>array</type><methodname>getimagesize</methodname>
     <methodparam><type>string</type><parameter>filename</parameter></methodparam>
     <methodparam choice="opt"><type>array</type><parameter>imageinfo</parameter></methodparam>
    </methodsynopsis>
   <para>
    The <function>getimagesize</function> function will determine the
    size of any <acronym>GIF</acronym>, <acronym>JPG</acronym>,
    <acronym>PNG</acronym>, <acronym>SWF</acronym>, 
    <acronym>SWC</acronym>, <acronym>PSD</acronym>, 
    <acronym>TIFF</acronym>, <acronym>BMP</acronym> or 
    <acronym>IFF</acronym> 
    image file and return the dimensions along with the file type and 
    a height/width text string to be used inside a normal 
    <acronym>HTML</acronym> <literal>IMG</literal> tag.
   </para>
   <para>
    Returns an array with 4 elements. Index 0 contains the width of
    the image in pixels. Index 1 contains the height.  Index 2 is a
    flag indicating the type of the image: 1 = GIF, 2 = JPG, 3 =
    PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(intel byte order),
    8 = TIFF(motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 =
    JB2, 13 = SWC, 14 = IFF. These values correspond to the IMAGETYPE
    constants that were added in PHP 4.3. Index 3 is a text string with 
    the correct height="yyy" width="xxx" string that can be used 
    directly in an IMG tag.
    <example>
     <title>getimagesize (file)</title>
     <programlisting role="php">
<![CDATA[
<?php
$size = getimagesize ("img/flag.jpg");
echo "<img src=\"img/flag.jpg\" {$size[3]}>";
?>
]]>
     </programlisting>
    </example>
   </para>
   <para>
    <example>
     <title>getimagesize (URL)</title>
     <programlisting role="php">
<![CDATA[
<?php $size = getimagesize ("http://www.example.com/gifs/logo.gif"); ?>
]]>
     </programlisting>
    </example>
   </para>
   <para>
    With <acronym>JPG</acronym> images, two extra indexes are returned:
    <literal>channels</literal> and <literal>bits</literal>.
    <literal>channels</literal> will be 3 for RGB pictures and 4 for CMYK
    pictures. <literal>bits</literal> is the number of bits for each color.
   </para>
   <para>
    Beginning with PHP 4.3, <literal>bits</literal> and
    <literal>channels</literal> are present for other image types, too.
    However, the presence of these values can be a bit confusing. As an
    example, <acronym>GIF</acronym> always uses 3 channels per pixel, but the
    number of bits per pixel cannot be calculated for an animated
    <acronym>GIF</acronym> with a global color table.
   </para>
   <para>
    Some formats may contain no image or may contain multiple images. In these
    cases, <function>getimagesize</function> might not be able to properly
    determine the image size. <function>getimagesize</function> will return
    zero for width and height in these cases.
   </para>
   <para>
    Beginning with PHP 4.3, <function>getimagesize</function> also returns an
    additional parameter, <literal>mime</literal>, that corresponds with the
    MIME type of the image.  This information can be used to deliver images
    with correct HTTP Content-type headers:
    <example>
     <title>getimagesize() and MIME types</title>
     <programlisting role="php">
<![CDATA[
<?php
$size = getimagesize ($filename);
$fp=fopen($filename, "rb");
if ($size && $fp) {
  header("Content-type: {$size['mime']}");
  fpassthru($fp);
  exit;
} else {
  // error
}
?>
]]>
     </programlisting>
    </example>
   </para>
   <para>
    If accessing the <parameter>filename</parameter> image is impossible,
    or if it isn't a valid picture, <function>getimagesize</function>
    will return &false; and generate a warning.
   </para>
   <para>
    The optional <parameter>imageinfo</parameter> parameter allows
    you to extract some extended information from the image
    file. Currently, this will return the different
    <acronym>JPG</acronym> APP markers as an associative array. Some
    programs use these APP markers to embed text information in
    images. A very common one is to embed <acronym>IPTC</acronym>
    <ulink url="&url.iptc;">&url.iptc;</ulink> information in the
    APP13 marker. You can use the <function>iptcparse</function>
    function to parse the binary APP13 marker into something
    readable.
    <example>
     <title>getimagesize() returning IPTC</title>
     <programlisting>
<![CDATA[
<?php
$size = getimagesize ("testimg.jpg",&$info);
if (isset ($info["APP13"])) {
    $iptc = iptcparse ($info["APP13"]);
    var_dump ($iptc);
}
?>
]]>
     </programlisting>
    </example>
    <note>
     <simpara>
      TIFF support was added in PHP 4.2.
     </simpara>
     <simpara>
      This function does not require the GD image library.
     </simpara>
     <simpara>
      See also <function>image_type_to_mime_type</function>, 
      <function>exif_imagetype</function>, <function>exif_read_data</function>
      and <function>exif_thumbnail</function>.
     </simpara>
     <simpara>
      URL support was added in PHP 4.0.5.
     </simpara>
    </note>
   </para>
  </refsect1>
 </refentry>

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