diff --git a/models/Thumbnail.php b/models/Thumbnail.php
index b650854..c7c45ba 100644
--- a/models/Thumbnail.php
+++ b/models/Thumbnail.php
@@ -9,6 +9,7 @@
 class Thumbnail
 {
 	private $image;
+	private $image_meta;
 	private $thumbnails;
 
 	private $properly_initialised;
@@ -23,7 +24,7 @@ class Thumbnail
 	const CROP_MODE_SLICE_CENTRE = 4;
 	const CROP_MODE_SLICE_BOTTOM = 5;
 
-	public function __construct($image)
+	public function __construct(Image $image)
 	{
 		$this->image      = $image;
 		$this->image_meta = $image->getMeta();
@@ -45,51 +46,45 @@ class Thumbnail
 		$thumb_selector = $this->width . 'x' . $this->height . $this->filename_suffix;
 		if (!empty($this->thumbnails[$thumb_selector]))
 		{
-			$thumb_path = '/' . $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
-			if (file_exists(THUMBSDIR . $thumb_path))
-				return THUMBSURL . $thumb_path;
+			$thumb_filename = $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
+			if (file_exists(THUMBSDIR . '/' . $thumb_filename))
+				return THUMBSURL . '/' . $thumb_filename;
 		}
 
 		// Do we have a custom thumbnail on file?
 		$custom_selector = 'custom_' . $this->width . 'x' . $this->height;
 		if (isset($this->image_meta[$custom_selector]))
 		{
-			$custom_thumb_path = '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
-			if (file_exists(ASSETSDIR . $custom_thumb_path))
+			$custom_filename = $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
+			if (file_exists(ASSETSDIR . '/' . $custom_filename))
 			{
-				// Ensure destination thumbnail directory exists.
-				if (!file_exists($this->image->getSubdir()))
-					@mkdir(THUMBSDIR . '/' . $this->image->getSubdir(), 0755, true);
-
 				// Copy the custom thumbail to the general thumbnail directory.
-				copy(ASSETSDIR . $custom_thumb_path, THUMBSDIR . $custom_thumb_path);
+				copy(ASSETSDIR . '/' . $custom_filename, THUMBSDIR . '/' . $custom_filename);
 
 				// Let's remember this for future reference.
 				$this->markAsGenerated($this->image_meta[$custom_selector]);
 
-				return THUMBSURL . $custom_thumb_path;
+				return THUMBSURL . '/' . $custom_filename;
 			}
 			else
 				throw new UnexpectedValueException('Custom thumbnail expected, but missing in file system!');
 		}
 
 		// Is this the right moment to generate a thumbnail, then?
-		if ($generate && array_key_exists($thumb_selector, $this->thumbnails))
+		if ($generate)
 		{
-			return $this->generate();
+			if (array_key_exists($thumb_selector, $this->thumbnails))
+				return $this->generate();
+			else
+				throw new Exception("Trying to generate a thumbnail not previously queued by the system\n" .
+					print_r(func_get_args(), true));
 		}
 
 		// If not, queue it for generation at another time, and return a URL to generate it with.
-		elseif (!$generate)
-		{
-			$this->markAsQueued();
-			return BASEURL . '/thumbnail/' . $this->image->getId() . '/' . $this->width . 'x' . $this->height . $this->filename_suffix . '/';
-		}
-
-		// Still here..? What are you up to? ..Sneaking?
 		else
 		{
-			throw new Exception("Trying to generate a thumbnail for selector " . $thumb_selector . ", which does not appear to have been requested by the system.\n" . print_r(func_get_args(), true));
+			$this->markAsQueued();
+			return BASEURL . '/thumbnail/' . $this->image->getId() . '/' . $thumb_selector . '/';
 		}
 	}
 
@@ -338,6 +333,8 @@ class Thumbnail
 			$thumb_selector = $this->width . 'x' . $this->height . $this->filename_suffix;
 			$this->thumbnails[$thumb_selector] = $filename !== 'NULL' ? $filename : '';
 		}
+		else
+			throw new UnexpectedValueException('Thumbnail queuing query failed');
 
 		return $success;
 	}