Index: includes/Linker.php
===================================================================
--- includes/Linker.php	(revision 17123)
+++ includes/Linker.php	(working copy)
@@ -456,7 +456,7 @@
 
 	/** @todo document */
 	function makeImageLinkObj( $nt, $label, $alt, $align = '', $width = false, $height = false, $framed = false,
-	  $thumb = false, $manual_thumb = '', $page = null )
+	  $thumb = false, $manual_thumb = '', $page = null, $link = '' )
 	{
 		global $wgContLang, $wgUser, $wgThumbLimits, $wgGenerateThumbnailOnParse;
 
@@ -506,7 +506,7 @@
 				$width = min( $img->getWidth(), $wgThumbLimits[$wopt] );
 			}
 
-			return $prefix.$this->makeThumbLinkObj( $img, $label, $alt, $align, $width, $height, $framed, $manual_thumb ).$postfix;
+			return $prefix.$this->makeThumbLinkObj( $img, $label, $alt, $align, $width, $height, $framed, $manual_thumb, $link ).$postfix;
 		}
 
 		if ( $width && $img->exists() ) {
@@ -544,30 +544,117 @@
 
 		wfDebug( "makeImageLinkObj2: '$width'x'$height'\n" );
 		$u = $nt->escapeLocalURL();
+		$target = self::determineImageLinkTarget ( $link, $u );
 		if ( $error ) {
 			$s = $error;
 		} elseif ( $url == '' ) {
 			$s = $this->makeBrokenImageLinkObj( $img->getTitle() );
 			//$s .= "<br />{$alt}<br />{$url}<br />\n";
 		} else {
-			$s = '<a href="'.$u.'" class="image" title="'.$alt.'">' .
-				 '<img src="'.$url.'" alt="'.$alt.'" ' .
+			$s = '<img src="'.$url.'" alt="'.$alt.'" ' .
 				 ( $width
 				 	? ( 'width="'.$width.'" height="'.$height.'" ' )
 				 	: '' ) .
-				 'longdesc="'.$u.'" /></a>';
+				 'longdesc="'.$u.'" />';
+			if ($target) $s = '<a href="'.$target.'" class="image" title="'.$alt.'">' . $s . '</a>';
 		}
 		if ( '' != $align ) {
 			$s = "<div class=\"float{$align}\"><span>{$s}</span></div>";
 		}
 		return str_replace("\n", ' ',$prefix.$s.$postfix);
 	}
+	
+	/**
+	 * @desc: There are 4 types of image links:
+	 *        1) The image description page (default).
+	 *        2) An internal image link (i.e. to another wiki page, not the image description page).
+	 *        3) An external image link, off to some other site.
+	 *        4) No link at all.
+	 */
+	static private function determineImageLinkTarget ( $text, $fallback_url ) {
+		global $wgAllowNoImageTarget, $wgAllowInternalImageTarget, $wgAllowExternalImageTarget;
 
+		// no special linking allowed, so just return.
+		if ( !$wgAllowNoImageTarget && !$wgAllowInternalImageTarget && !$wgAllowExternalImageTarget) {
+			return $fallback_url;
+		}
+
+		// if there was no attempt to use special linking, then no point in doing any work.
+		if ( !$text ) {
+			return $fallback_url;
+		}
+
+		// Requested no image link.
+		$mwNone =& MagicWord::get( 'img_none' );
+		if ($wgAllowNoImageTarget && ! is_null( $mwNone->matchVariableStartToEnd($text) ) ) {
+			return null;
+		}
+
+		// Requested an internal link.
+		if ($wgAllowInternalImageTarget) {
+			// this is taken from excerpts of the replaceInternalLinks() function.
+			$m = array();
+			$tc = Title::legalChars() . '#%';
+			$el = "/^\[\[([{$tc}]+)]]$/sD";
+			if ( preg_match($el, trim($text), $m) ) {
+				# Don't allow internal links to pages containing
+				# PROTO: where PROTO is a valid URL protocol; these
+				# should probably be external links, with one square
+				# bracket. Just use the default description link instead.
+				if (preg_match('/^(\b(?:' . wfUrlProtocols() . '))/', $m[1])) {
+					return $fallback_url;
+				}
+				$link = $m[1];
+				$nt = Title::newFromText( $link );
+				if( !$nt ) {
+					return $fallback_url;
+				}
+				// otherwise use the internal URL.
+				return $nt->escapeLocalURL();
+			}
+		}
+
+		// Requested an external link.
+		if ($wgAllowExternalImageTarget) {
+			// this is taken from the replaceExternalLinks() function.
+			$bits = preg_split( EXT_LINK_BRACKETED, $text, -1, PREG_SPLIT_DELIM_CAPTURE );
+			if ( empty ( $bits[1] ) ) {
+				return $fallback_url;
+			}
+
+			$external_url = $bits[1];
+
+			# The characters '<' and '>' (which were escaped by
+			# removeHTMLtags()) should not be included in
+			# URLs, per RFC 2396.
+			$m2 = array();
+			if (preg_match('/&(lt|gt);/', $external_url, $m2, PREG_OFFSET_CAPTURE)) {
+				$external_url = substr($external_url, 0, $m2[0][1]);
+			}
+
+			$external_url = Sanitizer::cleanUrl( $external_url );
+
+			# Register link in the output object.
+			# Replace unnecessary URL escape codes with the referenced character
+			# This prevents spammers from hiding links from the filters
+			$pasteurized = Parser::replaceUnusualEscapes( $external_url );
+			
+			//### Q: How to call this?
+			//### $this->mOutput->addExternalLink( $pasteurized );
+			//### Is there some kind of global variable, or a function or something to get this?
+			
+			return $external_url;
+		}
+
+		// The user gave us a link= parameter, but the link looks to be malformed. Use the standard image description linking as a fallback.
+		return $fallback_url;
+	}
+
 	/**
 	 * Make HTML for a thumbnail including image, border and caption
 	 * $img is an Image object
 	 */
-	function makeThumbLinkObj( $img, $label = '', $alt, $align = 'right', $boxwidth = 180, $boxheight=false, $framed=false , $manual_thumb = "" ) {
+	function makeThumbLinkObj( $img, $label = '', $alt, $align = 'right', $boxwidth = 180, $boxheight=false, $framed=false , $manual_thumb = "", $link = "" ) {
 		global $wgStylePath, $wgContLang, $wgGenerateThumbnailOnParse;
 		$thumbUrl = '';
 		$error = '';
@@ -622,6 +709,7 @@
 		}
 
 		$u = $img->getEscapeLocalURL();
+		$target = self::determineImageLinkTarget ( $link, $u );
 
 		$more = htmlspecialchars( wfMsg( 'thumbnail-more' ) );
 		$magnifyalign = $wgContLang->isRTL() ? 'left' : 'right';
@@ -639,10 +727,11 @@
 			$s .= $this->makeBrokenImageLinkObj( $img->getTitle() );
 			$zoomicon = '';
 		} else {
-			$s .= '<a href="'.$u.'" class="internal" title="'.$alt.'">'.
-				'<img src="'.$thumbUrl.'" alt="'.$alt.'" ' .
+			if ($target) $s .= '<a href="'.$target.'" class="internal" title="'.$alt.'">';
+			$s .= '<img src="'.$thumbUrl.'" alt="'.$alt.'" ' .
 				'width="'.$boxwidth.'" height="'.$boxheight.'" ' .
-				'longdesc="'.$u.'" /></a>';
+				'longdesc="'.$u.'" />';
+			if ($target) $s .= '</a>';
 			if ( $framed ) {
 				$zoomicon="";
 			} else {
@@ -698,8 +787,6 @@
 	 *
 	 * @param $title Title object.
 	 * @param $text  String: pre-sanitized HTML
-	 * @param $nourl Boolean: Mask absolute URLs, so the parser doesn't
-	 *                       linkify them (it is currently not context-aware)
 	 * @return string HTML
 	 *
 	 * @public
Index: includes/Parser.php
===================================================================
--- includes/Parser.php	(revision 17123)
+++ includes/Parser.php	(working copy)
@@ -436,7 +436,7 @@
 
 	/**
 	 * Replaces all occurrences of HTML-style comments and the given tags
-	 * in the text with a random marker and returns teh next text. The output
+	 * in the text with a random marker and returns the next text. The output
 	 * parameter $matches will be an associative array filled with data in
 	 * the form:
 	 *   'UNIQ-xxxxx' => array(
@@ -1681,12 +1681,6 @@
 				if ( $ns == NS_IMAGE ) {
 					wfProfileIn( "$fname-image" );
 					if ( !wfIsBadImage( $nt->getDBkey(), $this->mTitle ) ) {
-						# recursively parse links inside the image caption
-						# actually, this will parse them in any other parameters, too,
-						# but it might be hard to fix that, and it doesn't matter ATM
-						$text = $this->replaceExternalLinks($text);
-						$text = $this->replaceInternalLinks($text);
-
 						# cloak any absolute URLs inside the image markup, so replaceExternalLinks() won't touch them
 						$s .= $prefix . $this->armorLinks( $this->makeImage( $nt, $text ) ) . $trail;
 						$this->mOutput->addImage( $nt->getDBkey() );
@@ -4270,13 +4264,15 @@
 
 		# Check if the options text is of the form "options|alt text"
 		# Options are:
-		#  * thumbnail       	make a thumbnail with enlarge-icon and caption, alignment depends on lang
-		#  * left		no resizing, just left align. label is used for alt= only
-		#  * right		same, but right aligned
-		#  * none		same, but not aligned
-		#  * ___px		scale to ___ pixels width, no aligning. e.g. use in taxobox
-		#  * center		center the image
-		#  * framed		Keep original image size, no magnify-button.
+		#  * thumbnail   make a thumbnail with enlarge-icon and caption, alignment depends on lang
+		#  * left        no resizing, just left align. label is used for alt= only
+		#  * right       same, but right aligned
+		#  * none        same, but not aligned
+		#  * ___px       scale to ___ pixels width, no aligning. e.g. use in taxobox
+		#  * center      center the image
+		#  * framed      Keep original image size, no magnify-button.
+		#  * thumb=___	 use manually specified thumbnail.
+		#  * link=___	 Specify an image link target besides the image description page.
 
 		$part = explode( '|', $options);
 
@@ -4289,11 +4285,12 @@
 		$mwCenter =& MagicWord::get( 'img_center' );
 		$mwFramed =& MagicWord::get( 'img_framed' );
 		$mwPage   =& MagicWord::get( 'img_page' );
+		$mwLink   =& MagicWord::get( 'img_link' );
 		$caption = '';
 
 		$width = $height = $framed = $thumb = false;
 		$page = null;
-		$manual_thumb = '' ;
+		$manual_thumb = $link = '' ;
 
 		foreach( $part as $val ) {
 			if ( $wgUseImageResize && ! is_null( $mwThumb->matchVariableStartToEnd($val) ) ) {
@@ -4330,10 +4327,18 @@
 				}
 			} elseif ( ! is_null( $mwFramed->matchVariableStartToEnd($val) ) ) {
 				$framed=true;
+			} elseif ( ! is_null( $match = $mwLink->matchVariableStartToEnd($val) ) ) {
+				# use manually specified link target
+				$link = $match;
 			} else {
-				$caption = $val;
+				$caption .= ($caption ? "|" : "") . $val;
 			}
 		}
+		
+		# recursively parse links inside the image caption
+		$caption = $this->replaceExternalLinks($caption);
+		$caption = $this->replaceInternalLinks($caption);
+		
 		# Strip bad stuff out of the alt text
 		$alt = $this->replaceLinkHoldersText( $caption );
 
@@ -4345,7 +4350,7 @@
 
 		# Linker does the rest
 		$sk =& $this->mOptions->getSkin();
-		return $sk->makeImageLinkObj( $nt, $caption, $alt, $align, $width, $height, $framed, $thumb, $manual_thumb, $page );
+		return $sk->makeImageLinkObj( $nt, $caption, $alt, $align, $width, $height, $framed, $thumb, $manual_thumb, $page, $link );
 	}
 
 	/**
Index: includes/DefaultSettings.php
===================================================================
--- includes/DefaultSettings.php	(revision 17123)
+++ includes/DefaultSettings.php	(working copy)
@@ -2300,4 +2300,15 @@
 $wgEnableAPI = true;
 $wgEnableWriteAPI = false;
 
+/** 
+ * Options for whether an image can link to things besides the standard image description page.
+ * First allows users to specify an External link target for an image.
+ * Second allows users to specify an Internal wiki link target for an image.
+ * Third allows users to specify no link target for an image.
+ * Default setting for all three is off.
+ */
+$wgAllowExternalImageTarget = false;
+$wgAllowInternalImageTarget = false;
+$wgAllowNoImageTarget       = false;
+
 ?>
Index: languages/messages/MessagesEn.php
===================================================================
--- languages/messages/MessagesEn.php	(revision 17123)
+++ languages/messages/MessagesEn.php	(working copy)
@@ -247,6 +247,7 @@
 	'end'                    => array( 0,    '__END__'                ),
 	'img_thumbnail'          => array( 1,    'thumbnail', 'thumb'     ),
 	'img_manualthumb'        => array( 1,    'thumbnail=$1', 'thumb=$1'),
+	'img_link'               => array( 1,    'link=$1',  'target=$1'  ),
 	'img_right'              => array( 1,    'right'                  ),
 	'img_left'               => array( 1,    'left'                   ),
 	'img_none'               => array( 1,    'none'                   ),