I’ve always had a few pet-peeves with the readily available open source image galleries, namely that they are bulky and complex in many situations. They have some great features and they do well for many people, but for some (me) they’re just overkill.

A while back I set out to create a very simple web image gallery which would be contained in a single PHP file, and what I came up with has been in use for a while at http://images.johngauthier.com. There are a few configurable options, but for the most part it’s plug-and-play to have yourself a gallery:

<?php

class gallery {

	/* ***** ADJUSTABLE GLOBAL VARIABLES ***** */

	private $_strTitle = "John G. Gauthier's Gallery";	// Title for the gallery.
	private $_intThumbSize = 200; 						// Maximum width and height in pixels.
	private $_intThumbMargin = 3;						// Number of pixels between the thumbnail and the border.
	private $_strThumbDir = "_thumbs/";				// MUST end in '/', eg: "_thumbs/";

	/* *************************************** */
	/* DO NOT MODIFY THE CODE BELOW THIS POINT */
	/* *************************************** */

	private $_timeStart = 0;

	public function __construct() {
		$this->_timeStart = microtime(true);

		define('DS', DIRECTORY_SEPARATOR);
		define('URL_ENTIRE', $this->fetchEntireURL());
		define('URL_BASE', $this->fetchBaseURL());

		$this->checkRootViewAttempt();
		$this->checkClearThumbnailRequest();

		// If the thumbnail directory doesn't exist, create it.
		$strSubDirectory = (isset($_GET['d']))
			? "{$_GET['d']}/"
			: "";
		if (!is_dir($this->_strThumbDir . $strSubDirectory)) {
			mkdir ($this->_strThumbDir . $strSubDirectory, 0755, true);
		}

		$this->generateHeader();
		$this->buildAll($strSubDirectory);
		$this->generateFooter();
	}

	/*
	 * Loops through every directory, then every file, in the target folder and creates the necessary HTML structures.
	 */
	private function buildAll($strSubDirectory) {
		// Cycle through the contents of the folder, splitting the results into an array of directories (to be listed first) and an array of files (to be shown second)
		$fhDir = dir(getcwd() . DS . $strSubDirectory);
		while ($strItem = $fhDir->read()) {
			if (is_dir(getcwd() . DS . $strSubDirectory . DS . $strItem)) {
				// Check that this is a valid directory to include
				if ((($strItem != ".") && ($strItem != "..") && (substr($strItem,0,1) != '_')) || ($strItem == ".." && $strSubDirectory != "")) {
					$arrDirs[count($arrDirs)] = $strItem;
				}
			} else if (!ereg(".php",strtolower($strItem)) && !ereg("thumbs.db",strtolower($strItem))) {
				$arrFiles[count($arrFiles)] = $strItem;
			}
		}
		$fhDir->close();

		if (is_array($arrDirs))  sort($arrDirs);
		if (is_array($arrFiles)) sort($arrFiles);

		for ($i = 0; $i < count($arrDirs); $i++) {
			echo($this->buildDivForDir($strSubDirectory . $arrDirs[$i]));
		}

		for ($i = 0; $i < count($arrFiles); $i++) {
			/* Determine what kind of thumbnail we need to build. */
			if (ereg(".jpg",strtolower($arrFiles[$i])) ||
				ereg(".tif",strtolower($arrFiles[$i])) ||
				ereg(".gif",strtolower($arrFiles[$i])) ||
				ereg(".png",strtolower($arrFiles[$i])))
			{
				echo($this->buildDivForImage($strSubDirectory . $arrFiles[$i]));
			} else {
				echo($this->buildDivForOther($strSubDirectory . $arrFiles[$i]));
			}
		}
	}

	/*
	 * Build a div for a directory.
	 */
	private function buildDivForDir($strFilename) {
		// build a user-friendly file name.
		$strName = str_replace($_GET['d'], "", $strFilename);
		// if we are in the root directory, preface the name with '/' for readability.
		if ($_GET['d']=="") {
			$strName="/$strName";
		}
		// If the root is our parent, point at the base URL.
		$strURL = URL_BASE;
		if (strpos($strFilename,"..")>0) {
			// Replace name for clarification for non-DOS fluent folk.
			$strName = "Return to parent directory...";
			// Handle depth issues.
			// If we are deeper than one child, build the new URL.
			if ($strFilename != "..") {
				// Remove '/..' from the filename
				$strURL .= "?d=".substr($strFilename, 0, -3);
				// Remove one directory layer from the right
				$strURL = substr($strURL, 0, strrpos($strURL, "/"));
			}
		// Subdirectories
		} else {
			$strURL .= "?d={$strFilename}";
		}
		// Build the div to encapsulate the text.
		return "		<div class=\"outer\"><div class=\"front\" onclick=\"location.href='{$strURL}'\">{$strName}</div></div>\n";
	}

	/*
	 * Build a div for an image.
	 */
	private function buildDivForImage($strFilename) {
		// Build the div statement with thumbnail, with the div itself being a hyperlink to the full image
		return "		<div class=\"outer\"><div class=\"front\" onclick=\"location.href='{$strFilename}'\"><img style=\"border:0;\" src=\"{$this->buildThumb($strFilename)}\" alt=\"{$strFilename}\" title=\"{$this->formatFilename($strFilename)}\"></div></div>\n";
	}

	/*
	 * Build a div for a viewable/navigatable object other than a jpg image.
	 */
	private function buildDivForOther($strFilename) {
		// Build the div to encapsulate the text.
		return "		<div class=\"outer\"><div class=\"front\" onclick=\"location.href='{$strFilename}'\">{$this->formatFilename($strFilename)}</div></div>\n";
	}

	/*
	 * Construct a thumbnail image for an image file.
	 */
	private function buildThumb($strFilename) {
		$strThumbFilename = $this->_strThumbDir . substr($strFilename,0,(strlen($strFilename) - 4)) . substr($strFilename,(strlen($strFilename) - 4));

		// $arrDim[0] = width of the image in pixels.
		// $arrDim[1] = height of the image in pixels.
		// $arrDim[2] = 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

		// If the thumb exists AND it's the same size as what we're after, bail because we're done.
		if (file_exists($strThumbFilename)) {
			$arrThumbDim = getimagesize($strThumbFilename);
			if ($arrThumbDim[0] == $this->_intThumbSize || $arrThumbDim[1] == $this->_intThumbSize) {
				return $strThumbFilename;
			}
		}

		$arrDim = getimagesize($strFilename);

		// Get new sizes
		$intOrigRatio = $arrDim[0] / $arrDim[1];

		$intNewWidth = $this->_intThumbSize;
		$intNewHeight = $this->_intThumbSize;

		// Build new height, width
		if ($intNewWidth/$intNewHeight > $intOrigRatio) {
			$intNewWidth = $intNewHeight * $intOrigRatio;
		} else {
			$intNewHeight = $intNewWidth / $intOrigRatio;
		}

		// Load
		switch($arrDim[2]) {
			case 1: $objSource = imagecreatefromgif($strFilename); break;
			case 2: $objSource = imagecreatefromjpeg($strFilename); break;
			case 3: $objSource = imagecreatefrompng($strFilename); break;
		}

		if ($intNewWidth >= $arrDim[0] || $intNewHeight >= $arrDim[1]) {
			$intNewWidth = $arrDim[0];
			$intNewHeight = $arrDim[1];
		}

		// Resize
		$objThumb = imagecreatetruecolor($this->_intThumbSize, $this->_intThumbSize);
		imagefill($objThumb, 0, 0, imagecolorallocate($objThumb, 255, 255, 255));
		imagecopyresized($objThumb, $objSource, 0, 0, 0, 0, $intNewWidth, $intNewHeight, $arrDim[0], $arrDim[1]);

		// Save the thumbnail image
		switch($arrDim[2]) {
			case 1: imagegif($objThumb, $strThumbFilename); break;
			case 2: imagejpeg($objThumb, $strThumbFilename); break;
			case 3: imagepng($objThumb, $strThumbFilename); break;
		}

		// Clean up.
		imagedestroy($objSource);
		imagedestroy($objThumb);

		// Provide the parent function with the thumbnail file name.
		return $strThumbFilename;
	}

	/*
	 * Block attempts to view root file system.
	 *		Prevents a security exploit by ignoring all syntaxes for viewing a directory higher than web root.
	 */
	private function checkRootViewAttempt() {
		if ((substr($_GET['d'],0,1)=='.') || (substr($_GET['d'],0,1)=='/') || (substr($_GET['d'],0,1)=='\\')) {
			header("location: " . URL_BASE);
			exit();
		}
	}

	/*
	 * Destroys all thumbnails in a given directory.
	 *		If there is a problem with a thumbnail, the user has the ability to clear the thumbnails and cause them to be rebuilt on the next page load.
	 */
	private function checkClearThumbnailRequest() {
		// Per user request, clear existing thumbnails.
		if (isset($_GET['r'])) {
			$this->removeDirectory(getcwd() . DS . substr($this->_strThumbDir,0,-1) . DS . (isset($_GET['d']) ? $_GET['d'] : ""));
			header("location: " . URL_BASE);
			exit();
		}
	}

	/*
	 * Build a user-friendly file name.
	 */
	private function formatFilename($strFilename) {
		return str_replace("/", "", str_replace($_GET['d'], "", $strFilename));
	}

	private function generateFooter() {
?>
		<div class="clear"></div>
		<div class="w3c">
			<a href="http://validator.w3.org/check?uri=referer"><img src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01 Strict" height="31" width="88" style="border:0;"></a>
		</div>
		<div class="elapse">
			Page built in <?php echo(microtime(true) - $this->_timeStart); ?> seconds.<br>
			<i><a href="<?php echo(URL_ENTIRE . (isset($_GET['d']) ? "&amp;" : "?")); ?>r=1">Click here to rebuild the thumbnails above.</a></i>
		</div>
		<div class="clear"></div>
	</body>
</html>
<?php
	}

	private function generateHeader() {
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
		<style type="text/css">
			body {
				margin: 0px;
				padding: 0px;
			}
			div.title {
				font-size: 14px;
				font-weight: bold;
				margin: 9px;
			}
			div.outer {
				border: 1px solid #000;
				float: left;
				height: <?php echo($this->_intThumbSize + $this->_intThumbMargin*2); ?>px;
				margin: 5px;
				width: <?php echo($this->_intThumbSize + $this->_intThumbMargin*2); ?>px;
			}
			div.front {
				background-color: #FFF;
				cursor: pointer;
				height: <?php echo($this->_intThumbSize); ?>px;
				margin: <?php echo($this->_intThumbMargin); ?>px;
				width: <?php echo($this->_intThumbSize); ?>px;
			}
			div.clear {
				clear: both;
			}
			div.w3c {
				float: left;
				margin: 5px 10px;
			}
			div.elapse {
				float: right;
				font-size: 12px;
				margin-right: 2px;
				text-align: right;
			}
		</style>
		<title><?php echo($this->_strTitle); ?></title>
	</head>
	<body>
		<div class="title">
			<a href="<?php echo(URL_BASE); ?>"><?php echo($this->_strTitle); ?></a><?php echo((($_GET['d']) ? " - {$_GET['d']}" : "")); ?>
		</div>
<?php
	}

	/*
	 * Determine index.php's location in the site.
	 *		This will be used later to assemble hyperlinks and to prevent
	 *		navigation any higher up the tree than the starting point.
	 *
	 */
	private function fetchBaseURL() {
		// If our current URL contains a '?' then it and any PHP variables need to be pruned.
		return substr(URL_ENTIRE, 0, strpos(URL_ENTIRE, strstr(URL_ENTIRE,'?') ? '?' : 'index.php'));
	}

	/*
	 * Return the entire URL.
	 */
	private function fetchEntireURL() {
		$s = empty($_SERVER["HTTPS"])
			? ""
			: ($_SERVER["HTTPS"] == "on")
				? "s"
				: "";
	    $protocol = substr(strtolower($_SERVER["SERVER_PROTOCOL"]), 0, strpos(strtolower($_SERVER["SERVER_PROTOCOL"]), "/")).$s;
	    $port = ($_SERVER["SERVER_PORT"] == "80")
	    	? ""
	    	: (":".$_SERVER["SERVER_PORT"]);
		// Build the URL to return.
		$strURL = "{$protocol}://{$_SERVER["SERVER_NAME"]}{$port}{$_SERVER["REQUEST_URI"]}";
		if (!strstr($strURL,"index.php") && !strstr($strURL,'?')) {
			$strURL = "{$strURL}index.php";
		}
		return $strURL;
	}

	private function removeDirectory($strPath) {
        foreach(scandir($strPath) as $strFile){
            if ($strFile !== '.' && $strFile !== '..'){
                if (is_dir($strPath.'/'.$strFile)){
                    if (count(glob($strPath.'/'.$strFile.'/*')) > 0){
                        $this->removeDirectory($strPath.'/'.$strFile);
                    } else {
                        rmdir($strPath.'/'.$strFile);
                    }
                } else {
                    unlink($strPath.'/'.$strFile);
                }
            }
        }
        rmdir($strPath);
	}
};

new gallery();