diff --git a/core/imageboard.pack.php b/core/imageboard.pack.php
index 2067d0c5..36e9d050 100644
--- a/core/imageboard.pack.php
+++ b/core/imageboard.pack.php
@@ -609,6 +609,9 @@ class Image {
 	}
 
 	/**
+	 * WARNING: this description is no longer accurate, though it does get across
+	 * the general idea - the actual method has a few extra optimisiations
+	 *
 	 * "foo bar -baz user=foo" becomes
 	 *
 	 * SELECT * FROM images WHERE
@@ -742,32 +745,29 @@ class Image {
 				$have_pos = count($positive_tag_id_array) > 0;
 				$have_neg = count($negative_tag_id_array) > 0;
 
-				$sql = "SELECT images.* FROM images WHERE ";
+				$sql = "SELECT images.* FROM images WHERE images.id IN (";
 				if($have_pos) {
 					$positive_tag_id_list = join(', ', $positive_tag_id_array);
 					$sql .= "
-						images.id IN (
-							SELECT image_id
-							FROM image_tags
-							WHERE tag_id IN ($positive_tag_id_list)
-							GROUP BY image_id
-							HAVING COUNT(image_id)>=$positive_tag_count
-						)
+						SELECT image_id
+						FROM image_tags
+						WHERE tag_id IN ($positive_tag_id_list)
+						GROUP BY image_id
+						HAVING COUNT(image_id)>=$positive_tag_count
 					";
 				}
 				if($have_pos && $have_neg) {
-					$sql .= " AND ";
+					$sql .= " EXCEPT ";
 				}
 				if($have_neg) {
 					$negative_tag_id_list = join(', ', $negative_tag_id_array);
 					$sql .= "
-						images.id NOT IN (
-							SELECT image_id
-							FROM image_tags
-							WHERE tag_id IN ($negative_tag_id_list)
-						)
+						SELECT image_id
+						FROM image_tags
+						WHERE tag_id IN ($negative_tag_id_list)
 					";
 				}
+				$sql .= ")";
 				$query = new Querylet($sql);
 
 				if(strlen($img_search->sql) > 0) {
diff --git a/ext/index/main.php b/ext/index/main.php
index f5244d54..2fe58742 100644
--- a/ext/index/main.php
+++ b/ext/index/main.php
@@ -224,7 +224,11 @@ class Index extends Extension {
 		}
 		else if(preg_match("/^(filename|name)=([a-zA-Z0-9]*)$/i", $event->term, $matches)) {
 			$filename = strtolower($matches[2]);
-			$event->add_querylet(new Querylet('images.filename LIKE "%'.$filename.'%"'));
+			$event->add_querylet(new Querylet('images.filename LIKE :fn', array("fn"=>"%$filename%")));
+		}
+		else if(preg_match("/^(source)=([a-zA-Z0-9]*)$/i", $event->term, $matches)) {
+			$filename = strtolower($matches[2]);
+			$event->add_querylet(new Querylet('images.source LIKE :src', array("src"=>"%$filename%")));
 		}
 		else if(preg_match("/^posted(<|>|<=|>=|=)([0-9-]*)$/", $event->term, $matches)) {
 			$cmp = $matches[1];
diff --git a/ext/tag_list/main.php b/ext/tag_list/main.php
index 8f36345f..e90af658 100644
--- a/ext/tag_list/main.php
+++ b/ext/tag_list/main.php
@@ -394,46 +394,52 @@ class TagList extends Extension {
 		global $database;
 		global $config;
 
-		$wild_tags = Tag::explode($search);
-		// $search_tags = array();
+		$related_tags = $database->cache->get("related_tags:$search");
 
-		$tag_id_array = array();
-		$tags_ok = true;
-		foreach($wild_tags as $tag) {
-			$tag = str_replace("*", "%", $tag);
-			$tag = str_replace("?", "_", $tag);
-			$tag_ids = $database->get_col("SELECT id FROM tags WHERE tag LIKE :tag", array("tag"=>$tag));
-			// $search_tags = array_merge($search_tags,
-			//                  $database->get_col("SELECT tag FROM tags WHERE tag LIKE :tag", array("tag"=>$tag)));
-			$tag_id_array = array_merge($tag_id_array, $tag_ids);
-			$tags_ok = count($tag_ids) > 0;
-			if(!$tags_ok) break;
-		}
-		$tag_id_list = join(', ', $tag_id_array);
+		if(empty($related_tags)) {
+			$wild_tags = Tag::explode($search);
+			// $search_tags = array();
 
-		if($tags_ok) {
-			$query = "
-				SELECT t2.tag AS tag, COUNT(it2.image_id) AS calc_count
-				FROM
-					image_tags AS it1,
-					image_tags AS it2,
-					tags AS t1,
-					tags AS t2
-				WHERE
-					t1.id IN($tag_id_list)
-					AND it1.image_id=it2.image_id
-					AND it1.tag_id = t1.id
-					AND it2.tag_id = t2.id
-				GROUP BY t2.tag
-				ORDER BY calc_count
-				DESC LIMIT :limit
-			";
-			$args = array("limit"=>$config->get_int('tag_list_length'));
-
-			$related_tags = $database->get_all($query, $args);
-			if(count($related_tags) > 0) {
-				$this->theme->display_refine_block($page, $related_tags, $wild_tags);
+			$tag_id_array = array();
+			$tags_ok = true;
+			foreach($wild_tags as $tag) {
+				$tag = str_replace("*", "%", $tag);
+				$tag = str_replace("?", "_", $tag);
+				$tag_ids = $database->get_col("SELECT id FROM tags WHERE tag LIKE :tag", array("tag"=>$tag));
+				// $search_tags = array_merge($search_tags,
+				//                  $database->get_col("SELECT tag FROM tags WHERE tag LIKE :tag", array("tag"=>$tag)));
+				$tag_id_array = array_merge($tag_id_array, $tag_ids);
+				$tags_ok = count($tag_ids) > 0;
+				if(!$tags_ok) break;
 			}
+			$tag_id_list = join(', ', $tag_id_array);
+
+			if($tags_ok) {
+				$query = "
+					SELECT t2.tag AS tag, COUNT(it2.image_id) AS calc_count
+					FROM
+						image_tags AS it1,
+						image_tags AS it2,
+						tags AS t1,
+						tags AS t2
+					WHERE
+						t1.id IN($tag_id_list)
+						AND it1.image_id=it2.image_id
+						AND it1.tag_id = t1.id
+						AND it2.tag_id = t2.id
+					GROUP BY t2.tag
+					ORDER BY calc_count
+					DESC LIMIT :limit
+				";
+				$args = array("limit"=>$config->get_int('tag_list_length'));
+
+				$related_tags = $database->get_all($query, $args);
+				$database->cache->set("related_tags:$search", $related_tags, 60*60);
+			}
+		}
+
+		if(count($related_tags) > 0) {
+			$this->theme->display_refine_block($page, $related_tags, $wild_tags);
 		}
 	}
 // }}}
diff --git a/ext/upload/main.php b/ext/upload/main.php
index f88db765..06723691 100644
--- a/ext/upload/main.php
+++ b/ext/upload/main.php
@@ -215,7 +215,9 @@ class Upload extends Extension {
 
 	private function tags_for_upload_slot($id) {
 		if(isset($_POST["tags$id"])) {
-			$tags = array_merge(Tag::explode($_POST['tags']), Tag::explode($_POST["tags$id"]));
+			# merge then explode, not explode then merge - else
+			# one of the merges may create a surplus "tagme"
+			$tags = Tag::explode($_POST['tags'] . " " . $_POST["tags$id"]);
 		}
 		else {
 			$tags = Tag::explode($_POST['tags']);