diff --git a/contrib/tag_history/main.php b/contrib/tag_history/main.php
new file mode 100644
index 00000000..6ecd9adb
--- /dev/null
+++ b/contrib/tag_history/main.php
@@ -0,0 +1,219 @@
+<?php
+
+class Tag_History extends Extension {
+	public function receive_event($event) {
+		if(is_a($event, 'InitExtEvent')) {
+			// shimmie is being installed so call install to create the table.
+			global $config;
+			if($config->get_int("ext_tag_history_version") < 1) {
+				$this->install();
+			}
+		}
+
+		if(is_a($event, 'PageRequestEvent') && ($event->page == "tag_history"))
+		{
+			if($event->get_arg(0) == "revert")
+			{
+				// this is a request to revert to a previous version of the tags
+				$this->process_revert_request($_POST['image_id'], $_POST['revert']);
+			}
+			else
+			{
+				// must be an attempt to view a tag history
+				$image_id = int_escape($event->get_arg(0));
+				global $page;
+				global $config;
+				$page_heading = "Tag History: $image_id";
+				$page->set_title("Image $image_id Tag History");
+				$page->set_heading($page_heading);
+						
+				$page->add_block(new NavBlock());
+				$page->add_block(new Block("Tag History", $this->build_tag_history($image_id), "main", 10));
+			}
+			
+		}
+		if(is_a($event, 'DisplayingImageEvent'))
+		{
+			// handle displaying a link on the view page
+			global $page;
+			$page->add_block(new Block(null, $this->build_link($event->image->id), "main", 5));
+		}
+		if(is_a($event, 'ImageDeletionEvent'))
+		{
+			// handle removing of history when an image is deleted
+			$this->delete_all_tag_history($event->image->id);
+		}
+		if(is_a($event, 'SetupBuildingEvent')) {
+			$sb = new SetupBlock("Tag History");
+			$sb->add_label("Limit to ");
+			$sb->add_int_option("history_limit");
+			$sb->add_label(" entires per image");
+			$event->panel->add_block($sb);
+		}
+		if(is_a($event, 'ConfigSaveEvent')) {
+			$event->config->set_int_from_post("history_limit");
+		}
+		if(is_a($event, 'TagSetEvent')) {
+			$this->add_tag_history($event->image_id);
+		}
+
+	}
+	
+	protected function install()
+	{
+		global $database;
+		global $config;
+		$database->Execute("CREATE TABLE tag_histories
+		(
+    		id integer NOT NULL auto_increment PRIMARY KEY,
+    		image_id integer NOT NULL,
+    		tags text NOT NULL
+		)");
+		$config->set_int("ext_tag_history_version", 1);
+	}
+	
+	private function process_revert_request($image_id, $revert_id)
+	{
+		// this function is called when a revert request is received
+		global $page;
+		// check for the nothing case
+		if($revert_id=="nothing")
+		{
+			// tried to set it too the same thing so ignore it (might be a bot)
+			// go back to the index page with you
+			$page->set_mode("redirect");
+			$page->set_redirect(make_link("index"));
+			return;
+		}
+		
+		$revert_id = int_escape($revert_id);
+		$image_id = int_escape($image_id);
+		
+		// lets get this revert id assuming it exists
+		$result = $this->get_tag_history_from_revert($revert_id);
+		
+		if($result==null)
+		{
+			// 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.
+			die("Error: No tag history with specified id was found.");
+		}
+		
+		// lets get the values out of the result
+		$stored_result_id = $result->fields['id'];
+		$stored_image_id = $result->fields['image_id'];
+		$stored_tags = $result->fields['tags'];
+		
+		if($image_id!=$stored_image_id)
+		{
+			// wth is going on there ids should be the same otherwise we are trying
+			// to edit another image... banhammer this user... j/k
+			die("Error: Mismatch in history image ids.");
+		}
+		
+		// all should be ok so we can revert by firing the SetUserTags event.
+		send_event(new TagSetEvent($image_id, $stored_tags));
+		
+		// all should be done now so redirect the user back to the image
+		$page->set_mode("redirect");
+		$page->set_redirect(make_link("post/view/$image_id"));
+	}
+	
+	
+	
+	private function build_tag_history($image_id)
+	{
+		// this function is called when user tries to view tag history of an image
+		// check if the image exists
+		global $database;
+		$image = $database->get_image($image_id);
+		if($image==null)return "<strong>No image with the specified id currently exists</strong>";
+				
+		// get the current images tags
+		$current_tags = html_escape(implode(' ', $image->get_tag_array()));
+		//$current_tags = $image->cached_tags;
+		
+		// get any stored tag histories
+		$result = $this->get_tag_history_from_id($image_id);
+		$html =  "<div style='text-align: left'>";
+		$html .= "<br><form enctype='multipart/form-data' action='".make_link("tag_history/revert")."' method='POST'>\n";
+		$html .= "<input type='hidden' name='image_id' value='$image_id'>\n";
+		$html .= "<ul style='list-style-type:none;'>\n";
+		$html .= "<li><input type='radio' name='revert' value='nothing' checked>$current_tags (<strong>current</strong>)<br></li>\n";
+		
+		$end_string = "<input type='submit' value='Revert'></ul></form></div>";
+		// check for no stored history
+		if($result==null) return $html.$end_string;
+		
+		// process each one
+		while(!$result->EOF)
+		{
+			$fields = $result->fields;
+			$current_id = $fields['id'];
+			$current_tags = $fields['tags'];
+			$html .= "<li><input type='radio' name='revert' value='$current_id'>$current_tags<br></li>\n";
+			$result->MoveNext();	
+		}
+		$html .= $end_string;
+		
+		// now return the finished html
+		return $html;
+	}
+	
+	public function get_tag_history_from_revert($revert_id)
+	{
+		global $database;
+		$row = $database->execute( "SELECT * FROM tag_histories WHERE id = ?", array($revert_id));
+		return ($row ? $row : null);
+	}
+	
+	public function get_tag_history_from_id($image_id)
+	{
+		global $database;
+		$row = $database->execute( "SELECT * FROM tag_histories WHERE image_id = ? ORDER BY id DESC", array($image_id));
+		return ($row ? $row : null);
+	}
+	
+	private function build_link($image_id)
+	{
+		// this function is called when a user is viewing an image
+		return "<a href='".make_link("tag_history/$image_id")."'>Tag History</a>\n";
+	}
+	
+	private function delete_all_tag_history($image_id)
+	{
+		// this function is called when an image has been deleted
+		global $database;
+		$database->execute("DELETE FROM tag_histories WHERE image_id = ?", array($image_id));
+	}
+
+	private function add_tag_history($image_id)
+	{
+		// this function is called just before an images tag are changed
+		global $database;
+		global $config;
+		
+		// get the old tags
+		$image = $database->get_image($image_id);
+		$tags = $image->get_tag_array();
+		if(count($tags)==0)return;
+		$tags = implode(' ',$tags);
+		
+		// add a history entry		
+		$allowed = $config->get_int("history_limit",10);
+		if($allowed<=0)return;
+		$row = $database->execute("INSERT INTO tag_histories(image_id, tags) VALUES (?, ?)", array($image_id, $tags));
+		$entries = $database->db->GetOne("SELECT COUNT(*) FROM `tag_histories` WHERE image_id = ?", array($image_id));
+		
+		// if needed remove oldest one
+		if($entries > $allowed)
+		{
+			// TODO: Make these queries better
+			$min_id = $database->db->GetOne("SELECT MIN(id) FROM tag_histories WHERE image_id = ?", array($image_id));
+			$database->execute("DELETE FROM tag_histories WHERE id = ?", array($min_id));
+		}
+	}
+}
+add_event_listener(new Tag_History(), 40); // early, so that old tags can be archived before new ones are set
+?>