Check PHP GD library support

gd-lib-test.php

<?php

// Displays details of GD support on your server

echo '<div style="margin: 10px;">';

echo '<p style="color: #444444; font-size: 130%;">GD is ';

if (\function_exists('gd_info')) {
    echo '<span style="color: #00AA00; font-weight: bold;">supported</span> by your server!</p>';

    $gd = \gd_info();

    foreach ($gd as $k => $v) {
        echo '<div style="width: 340px; border-bottom: 1px solid #DDDDDD; padding: 2px;">';
        echo '<span style="float: left;width: 300px;">' . $k . '</span> ';

        if ($v) {
            echo '<span style="color: #00AA00; font-weight: bold;">Yes</span>';
        } else {
            echo '<span style="color: #EE0000; font-weight: bold;">No</span>';
        }

        echo '<div style="clear:both;"><!-- --></div></div>';
    }
} else {
    echo '<span style="color: #EE0000; font-weight: bold;">not supported</span> by your server!</p>';
}

echo '<p>by <a href="http://www.dagondesign.com">dagondesign.com</a></p>';

echo '</div>';