htmlpurifier/library/HTMLPurifier/HTMLModule/Image.php

<?php

/**
 * XHTML 1.1 Image Module provides basic image embedding.
 * @note There is specialized code for removing empty images in
 *       HTMLPurifier_Strategy_RemoveForeignElements
 */
class HTMLPurifier_HTMLModule_Image extends HTMLPurifier_HTMLModule
{

    public $name = 'Image';

    public function setup($config) {
        $max = $config->get('HTML', 'MaxImgLength');
        $img = $this->addElement(
            'img', 'Inline', 'Empty', 'Common',
            array(
                'alt*' => 'Text',
                // According to the spec, it's Length, but percents can
                // be abused, so we allow only Pixels.
                'height' => 'Pixels#' . $max,
                'width'  => 'Pixels#' . $max,
                'longdesc' => 'URI',
                'src*' => new HTMLPurifier_AttrDef_URI(true), // embedded
            )
        );
        if ($max === null || $config->get('HTML', 'Trusted')) {
            $img->attr['height'] =
            $img->attr['width'] = 'Length';
        }

        // kind of strange, but splitting things up would be inefficient
        $img->attr_transform_pre[] =
        $img->attr_transform_post[] =
            new HTMLPurifier_AttrTransform_ImgRequired();
    }

}