diff --git a/ext/source_history/main.php b/ext/source_history/main.php
new file mode 100644
index 00000000..68d748de
--- /dev/null
+++ b/ext/source_history/main.php
@@ -0,0 +1,376 @@
+<?php
+/*
+ * Name: Source History
+ * Author: Shish, copied from Source History
+ * Description: Keep a record of source changes, and allows you to revert changes.
+ */
+
+class Source_History extends Extension {
+	// in before source are actually set, so that "get current source" works
+	public function get_priority() {return 40;}
+
+	public function onInitExt(InitExtEvent $event) {
+		global $config;
+		$config->set_default_int("history_limit", -1);
+
+		// shimmie is being installed so call install to create the table.
+		if($config->get_int("ext_source_history_version") < 3) {
+			$this->install();
+		}
+	}
+
+	public function onAdminBuilding(AdminBuildingEvent $event) {
+		$this->theme->display_admin_block();
+	}
+
+	public function onPageRequest(PageRequestEvent $event) {
+		global $config, $page, $user;
+
+		if($event->page_matches("source_history/revert")) {
+			// this is a request to revert to a previous version of the source
+			if($user->can("edit_image_tag")) {
+				if(isset($_POST['revert'])) {
+					$this->process_revert_request($_POST['revert']);
+				}
+			}
+		}
+		else if($event->page_matches("source_history/bulk_revert")) {
+			if($user->can("bulk_edit_image_tag") && $user->check_auth_token()) {
+				$this->process_bulk_revert_request();
+			}
+		}
+		else if($event->page_matches("source_history/all")) {
+			$page_id = int_escape($event->get_arg(0));
+			$this->theme->display_global_page($page, $this->get_global_source_history($page_id), $page_id);
+		}
+		else if($event->page_matches("source_history") && $event->count_args() == 1) {
+			// must be an attempt to view a source history
+			$image_id = int_escape($event->get_arg(0));
+			$this->theme->display_history_page($page, $image_id, $this->get_source_history_from_id($image_id));
+		}
+	}
+	
+	public function onImageAdminBlockBuilding(ImageAdminBlockBuildingEvent $event) {
+		$event->add_part("
+			<form action='".make_link("source_history/{$event->image->id}")."' method='GET'>
+				<input type='submit' value='View Source History'>
+			</form>
+		", 20);
+	}
+
+	/*
+	// disk space is cheaper than manually rebuilding history,
+	// so let's default to -1 and the user can go advanced if
+	// they /really/ want to
+	public function onSetupBuilding(SetupBuildingEvent $event) {
+		$sb = new SetupBlock("Source History");
+		$sb->add_label("Limit to ");
+		$sb->add_int_option("history_limit");
+		$sb->add_label(" entires per image");
+		$sb->add_label("<br>(-1 for unlimited)");
+		$event->panel->add_block($sb);
+	}
+	*/
+
+	public function onSourceSet(SourceSetEvent $event) {
+		$this->add_source_history($event->image, $event->source);
+	}
+
+	public function onUserBlockBuilding(UserBlockBuildingEvent $event) {
+		global $user;
+		if($user->can("bulk_edit_image_tag")) {
+			$event->add_link("Source Changes", make_link("source_history/all/1"));
+		}
+	}
+	
+	protected function install() {
+		global $database, $config;
+
+		if($config->get_int("ext_source_history_version") < 1) {
+			$database->create_table("source_histories", "
+	    		id SCORE_AIPK,
+	    		image_id INTEGER NOT NULL,
+				user_id INTEGER NOT NULL,
+				user_ip SCORE_INET NOT NULL,
+	    		source TEXT NOT NULL,
+				date_set DATETIME NOT NULL,
+				INDEX(image_id),
+				FOREIGN KEY (image_id) REFERENCES images(id) ON DELETE CASCADE,
+				FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+			");
+			$config->set_int("ext_source_history_version", 3);
+		}
+		
+		if($config->get_int("ext_source_history_version") == 1) {
+			$database->Execute("ALTER TABLE source_histories ADD COLUMN user_id INTEGER NOT NULL");
+			$database->Execute("ALTER TABLE source_histories ADD COLUMN date_set DATETIME NOT NULL");
+			$config->set_int("ext_source_history_version", 2);
+		}
+
+		if($config->get_int("ext_source_history_version") == 2) {
+			$database->Execute("ALTER TABLE source_histories ADD COLUMN user_ip CHAR(15) NOT NULL");
+			$config->set_int("ext_source_history_version", 3);
+		}
+	}
+	
+	/*
+	 * this function is called when a revert request is received
+	 */
+	private function process_revert_request($revert_id) {
+		global $page;
+
+		$revert_id = int_escape($revert_id);
+
+		// check for the nothing case
+		if($revert_id < 1) {
+			$page->set_mode("redirect");
+			$page->set_redirect(make_link());
+			return;
+		}
+		
+		// lets get this revert id assuming it exists
+		$result = $this->get_source_history_from_revert($revert_id);
+		
+		if(empty($result)) {
+			// there is no history entry with that id so either the image was deleted
+			// while the user was viewing the history, someone is playing with form
+			// variables or we have messed up in code somewhere.
+			/* calling die() is probably not a good idea, we should throw an Exception */
+			die("Error: No source history with specified id was found.");
+		}
+		
+		// lets get the values out of the result
+		$stored_result_id = $result['id'];
+		$stored_image_id = $result['image_id'];
+		$stored_source = $result['source'];
+		
+		log_debug("source_history", 'Reverting source of Image #'.$stored_image_id.' to ['.$stored_source.']');
+		// all should be ok so we can revert by firing the SetUserSources event.
+		send_event(new SourceSetEvent(Image::by_id($stored_image_id), $stored_source));
+		
+		// all should be done now so redirect the user back to the image
+		$page->set_mode("redirect");
+		$page->set_redirect(make_link('post/view/'.$stored_image_id));
+	}
+
+	protected function process_bulk_revert_request() {
+		if (isset($_POST['revert_name']) && !empty($_POST['revert_name'])) {
+			$revert_name = $_POST['revert_name'];
+		}
+		else {
+			$revert_name = null;
+		}
+
+		if (isset($_POST['revert_ip']) && !empty($_POST['revert_ip'])) {
+			$revert_ip = filter_var($_POST['revert_ip'], FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE);
+			
+			if ($revert_ip === false) {
+				// invalid ip given.
+				$this->theme->display_admin_block('Invalid IP');
+				return;
+			}
+		}
+		else {
+			$revert_ip = null;
+		}
+		
+		if (isset($_POST['revert_date']) && !empty($_POST['revert_date'])) {
+			if (isValidDate($_POST['revert_date']) ){
+				$revert_date = addslashes($_POST['revert_date']); // addslashes is really unnecessary since we just checked if valid, but better safe.
+			}
+			else {
+				$this->theme->display_admin_block('Invalid Date');
+				return;
+			}
+		}
+		else {
+			$revert_date = null;
+		}
+		
+		set_time_limit(0); // reverting changes can take a long time, disable php's timelimit if possible.
+		
+		// Call the revert function.
+		$this->process_revert_all_changes($revert_name, $revert_ip, $revert_date);
+		// output results
+		$this->theme->display_revert_ip_results();
+	}
+	
+	public function get_source_history_from_revert(/*int*/ $revert_id) {
+		global $database;
+		$row = $database->get_row("
+				SELECT source_histories.*, users.name
+				FROM source_histories
+				JOIN users ON source_histories.user_id = users.id
+				WHERE source_histories.id = ?", array($revert_id));
+		return ($row ? $row : null);
+	}
+
+	public function get_source_history_from_id(/*int*/ $image_id) {
+		global $database;
+		$row = $database->get_all("
+				SELECT source_histories.*, users.name
+				FROM source_histories
+				JOIN users ON source_histories.user_id = users.id
+				WHERE image_id = ?
+				ORDER BY source_histories.id DESC",
+				array($image_id));
+		return ($row ? $row : array());
+	}
+
+	public function get_global_source_history($page_id) {
+		global $database;
+		$row = $database->get_all("
+				SELECT source_histories.*, users.name
+				FROM source_histories
+				JOIN users ON source_histories.user_id = users.id
+				ORDER BY source_histories.id DESC
+				LIMIT 100 OFFSET :offset
+		", array("offset" => ($page_id-1)*100));
+		return ($row ? $row : array());
+	}
+	
+	/*
+	 * This function attempts to revert all changes by a given IP within an (optional) timeframe.
+	 */
+	public function process_revert_all_changes($name, $ip, $date) {
+		global $database;
+		
+		$select_code = array();
+		$select_args = array();
+
+		if(!is_null($name)) {
+			$duser = User::by_name($name);
+			if(is_null($duser)) {
+				$this->theme->add_status($name, "user not found");
+				return;
+			}
+			else {
+				$select_code[] = 'user_id = ?';
+				$select_args[] = $duser->id;
+			}
+		}
+
+		if(!is_null($date)) {
+			$select_code[] = 'date_set >= ?';
+			$select_args[] = $date;
+		}
+
+		if(!is_null($ip)) {
+			$select_code[] = 'user_ip = ?';
+			$select_args[] = $ip;
+		}
+
+		if(count($select_code) == 0) {
+			log_error("source_history", "Tried to mass revert without any conditions");
+			return;
+		}
+
+		log_info("source_history", 'Attempting to revert edits where '.implode(" and ", $select_code)." (".implode(" / ", $select_args).")");
+		
+		// Get all the images that the given IP has changed source on (within the timeframe) that were last editied by the given IP
+		$result = $database->get_col('
+				SELECT t1.image_id
+				FROM source_histories t1
+				LEFT JOIN source_histories t2 ON (t1.image_id = t2.image_id AND t1.date_set < t2.date_set)
+				WHERE t2.image_id IS NULL
+				AND t1.image_id IN ( select image_id from source_histories where '.implode(" AND ", $select_code).') 
+				ORDER BY t1.image_id
+		', $select_args);
+	
+		foreach($result as $image_id) {
+			// Get the first source history that was done before the given IP edit
+			$row = $database->get_row('
+				SELECT id, source
+				FROM source_histories
+				WHERE image_id='.$image_id.'
+				AND NOT ('.implode(" AND ", $select_code).')
+				ORDER BY date_set DESC LIMIT 1
+			', $select_args);
+			
+			if (empty($row)) {
+				// we can not revert this image based on the date restriction.
+				// Output a message perhaps?
+			}
+			else {
+				$revert_id = $row['id'];
+				$result = $this->get_source_history_from_revert($revert_id);
+				
+				if(empty($result)) {
+					// there is no history entry with that id so either the image was deleted
+					// while the user was viewing the history,  or something messed up
+					/* calling die() is probably not a good idea, we should throw an Exception */
+					die('Error: No source history with specified id ('.$revert_id.') was found in the database.'."\n\n".
+						'Perhaps the image was deleted while processing this request.');
+				}
+				
+				// lets get the values out of the result
+				$stored_result_id = $result['id'];
+				$stored_image_id = $result['image_id'];
+				$stored_source = $result['source'];
+				
+				log_debug("source_history", 'Reverting source of Image #'.$stored_image_id.' to ['.$stored_source.']');
+				// all should be ok so we can revert by firing the SetSources event.
+				send_event(new SourceSetEvent(Image::by_id($stored_image_id), $stored_source));
+				$this->theme->add_status('Reverted Change','Reverted Image #'.$image_id.' to Source History #'.$stored_result_id.' ('.$row['source'].')');
+			}
+		}
+
+		log_info("source_history", 'Reverted '.count($result).' edits.');
+	}
+	
+	/*
+	 * this function is called just before an images source is changed
+	 */
+	private function add_source_history($image, $source) {
+		global $database, $config, $user;
+
+		$new_source = $source;
+		$old_source = $image->source;
+		
+		if($new_source == $old_source) return;
+		
+		if(empty($old_source)) {
+			/* no old source, so we are probably adding the image for the first time */
+			log_debug("source_history", "adding new source history: [$new_source]");
+		}
+		else {
+			log_debug("source_history", "adding source history: [$old_source] -> [$new_source]");
+		}
+		
+		$allowed = $config->get_int("history_limit");
+		if($allowed == 0) return;
+		
+		// if the image has no history, make one with the old source
+		$entries = $database->get_one("SELECT COUNT(*) FROM source_histories WHERE image_id = ?", array($image->id));
+		if($entries == 0 && !empty($old_source)) {
+			$database->execute("
+				INSERT INTO source_histories(image_id, source, user_id, user_ip, date_set)
+				VALUES (?, ?, ?, ?, now())",
+				array($image->id, $old_source, $config->get_int('anon_id'), '127.0.0.1'));
+			$entries++;
+		}
+
+		// add a history entry	
+		$row = $database->execute("
+				INSERT INTO source_histories(image_id, source, user_id, user_ip, date_set)
+				VALUES (?, ?, ?, ?, now())",
+				array($image->id, $new_source, $user->id, $_SERVER['REMOTE_ADDR']));
+		$entries++;
+		
+		// if needed remove oldest one
+		if($allowed == -1) return;
+		if($entries > $allowed) {
+			// TODO: Make these queries better
+			/*
+				MySQL does NOT allow you to modify the same table which you use in the SELECT part.
+				Which means that these will probably have to stay as TWO separate queries...
+				
+				http://dev.mysql.com/doc/refman/5.1/en/subquery-restrictions.html
+				http://stackoverflow.com/questions/45494/mysql-error-1093-cant-specify-target-table-for-update-in-from-clause
+			*/
+			$min_id = $database->get_one("SELECT MIN(id) FROM source_histories WHERE image_id = ?", array($image->id));
+			$database->execute("DELETE FROM source_histories WHERE id = ?", array($min_id));
+		}
+	}
+}
+?>
diff --git a/ext/source_history/theme.php b/ext/source_history/theme.php
new file mode 100644
index 00000000..29bcc019
--- /dev/null
+++ b/ext/source_history/theme.php
@@ -0,0 +1,137 @@
+<?php
+class Source_HistoryTheme extends Themelet {
+	var $messages = array();
+
+	public function display_history_page(Page $page, /*int*/ $image_id, /*array*/ $history) {
+		global $user;
+		$start_string = "
+			<div style='text-align: left'>
+				".make_form(make_link("source_history/revert"))."
+					<ul style='list-style-type:none;'>
+		";
+
+		$history_list = "";
+		$n = 0;
+		foreach($history as $fields)
+		{
+			$n++;
+			$current_id = $fields['id'];
+			$current_source = html_escape($fields['source']);
+			$name = $fields['name'];
+			$h_ip = $user->can("view_ip") ? " ".show_ip($fields['user_ip'], "Sourcing Image #$image_id as '$current_source'") : "";
+			$setter = "<a href='".make_link("user/".url_escape($name))."'>".html_escape($name)."</a>$h_ip";
+
+			$selected = ($n == 2) ? " checked" : "";
+
+			$history_list .= "
+				<li>
+					<input type='radio' name='revert' id='$current_id' value='$current_id'$selected>
+					<label for='$current_id'>$current_source (Set by $setter)</label>
+				</li>
+				";
+		}
+
+		$end_string = "
+					</ul>
+					<input type='submit' value='Revert To'>
+				</form>
+			</div>
+		";
+		$history_html = $start_string . $history_list . $end_string;
+
+		$page->set_title('Image '.$image_id.' Source History');
+		$page->set_heading('Source History: '.$image_id);
+		$page->add_block(new NavBlock());
+		$page->add_block(new Block("Source History", $history_html, "main", 10));
+	}
+
+	public function display_global_page(Page $page, /*array*/ $history, /*int*/ $page_number) {
+		$start_string = "
+			<div style='text-align: left'>
+				".make_form(make_link("source_history/revert"))."
+					<ul style='list-style-type:none;'>
+		";
+		$end_string = "
+					</ul>
+					<input type='submit' value='Revert To'>
+				</form>
+			</div>
+		";
+
+		global $user;
+		$history_list = "";
+		foreach($history as $fields)
+		{
+			$current_id = $fields['id'];
+			$image_id = $fields['image_id'];
+			$current_source = html_escape($fields['source']);
+			$name = $fields['name'];
+			$h_ip = $user->can("view_ip") ? " ".show_ip($fields['user_ip'], "Sourcing Image #$image_id as '$current_source'") : "";
+			$setter = "<a href='".make_link("user/".url_escape($name))."'>".html_escape($name)."</a>$h_ip";
+
+			$history_list .= '
+				<li>
+					<input type="radio" name="revert" value="'.$current_id.'">
+					<a href="'.make_link('post/view/'.$image_id).'">'.$image_id.'</a>:
+					'.$current_source.' (Set by '.$setter.')
+				</li>
+			';
+		}
+
+		$history_html = $start_string . $history_list . $end_string;
+		$page->set_title("Global Source History");
+		$page->set_heading("Global Source History");
+		$page->add_block(new Block("Source History", $history_html, "main", 10));
+
+
+		$h_prev = ($page_number <= 1) ? "Prev" :
+			'<a href="'.make_link('source_history/all/'.($page_number-1)).'">Prev</a>';
+		$h_index = "<a href='".make_link()."'>Index</a>";
+		$h_next = '<a href="'.make_link('source_history/all/'.($page_number+1)).'">Next</a>';
+
+		$nav = $h_prev.' | '.$h_index.' | '.$h_next;
+		$page->add_block(new Block("Navigation", $nav, "left"));
+	}
+
+	/*
+	 * Add a section to the admin page.
+	 */
+	public function display_admin_block(/*string*/ $validation_msg='') {
+		global $page;
+		
+		if (!empty($validation_msg)) {
+			$validation_msg = '<br><b>'. $validation_msg .'</b>';
+		}
+		
+		$html = '
+			Revert source changes/edit by a specific IP address or username.
+			<br>You can restrict the time frame to revert these edits as well.
+			<br>(Date format: 2011-10-23)
+			'.$validation_msg.'
+
+			<br><br>'.make_form(make_link("source_history/bulk_revert"), 'POST')."
+				<table class='form'>
+					<tr><th>Username</th>        <td><input type='text' name='revert_name' size='15'></td></tr>
+					<tr><th>IP&nbsp;Address</th> <td><input type='text' name='revert_ip' size='15'></td></tr>
+					<tr><th>Date&nbsp;range</th> <td><input type='text' name='revert_date' size='15'></td></tr>
+					<tr><td colspan='2'><input type='submit' value='Revert'></td></tr>
+				</table>
+			</form>
+		";
+		$page->add_block(new Block("Mass Source Revert", $html));
+	}
+	
+	/*
+	 * Show a standard page for results to be put into
+	 */
+	public function display_revert_ip_results() {
+		global $page;
+		$html = implode($this->messages, "\n");
+		$page->add_block(new Block("Bulk Revert Results", $html));
+	}
+	
+	public function add_status(/*string*/ $title, /*string*/ $body) {
+		$this->messages[] = '<p><b>'. $title .'</b><br>'. $body .'</p>';
+	}
+}
+?>