diff --git a/models/Thumbnail.php b/models/Thumbnail.php
index d0b982f..b650854 100644
--- a/models/Thumbnail.php
+++ b/models/Thumbnail.php
@@ -3,7 +3,7 @@
  * Thumbnail.php
  * Contains key class Thumbnail.
  *
- * Kabuki CMS (C) 2013-2015, Aaron van Geffen
+ * Kabuki CMS (C) 2013-2020, Aaron van Geffen
  *****************************************************************************/
 
 class Thumbnail
@@ -45,24 +45,29 @@ class Thumbnail
 		$thumb_selector = $this->width . 'x' . $this->height . $this->filename_suffix;
 		if (!empty($this->thumbnails[$thumb_selector]))
 		{
-			if (file_exists(THUMBSDIR . '/' . $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector]))
-				return THUMBSURL . '/' . $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
+			$thumb_path = '/' . $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
+			if (file_exists(THUMBSDIR . $thumb_path))
+				return THUMBSURL . $thumb_path;
 		}
 
 		// Do we have a custom thumbnail on file?
 		$custom_selector = 'custom_' . $this->width . 'x' . $this->height;
 		if (isset($this->image_meta[$custom_selector]))
 		{
-			if (file_exists(ASSETSDIR . '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector]))
+			$custom_thumb_path = '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
+			if (file_exists(ASSETSDIR . $custom_thumb_path))
 			{
+				// Ensure destination thumbnail directory exists.
+				if (!file_exists($this->image->getSubdir()))
+					@mkdir(THUMBSDIR . '/' . $this->image->getSubdir(), 0755, true);
+
 				// Copy the custom thumbail to the general thumbnail directory.
-				copy(ASSETSDIR . '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector],
-					THUMBSDIR . '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector]);
+				copy(ASSETSDIR . $custom_thumb_path, THUMBSDIR . $custom_thumb_path);
 
 				// Let's remember this for future reference.
 				$this->markAsGenerated($this->image_meta[$custom_selector]);
 
-				return THUMBSURL . '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
+				return THUMBSURL . $custom_thumb_path;
 			}
 			else
 				throw new UnexpectedValueException('Custom thumbnail expected, but missing in file system!');
@@ -84,7 +89,7 @@ class Thumbnail
 		// Still here..? What are you up to? ..Sneaking?
 		else
 		{
-			throw new Exception("Trying to generate a thumbnail for values that were not previously initialised by the system?\n" . print_r(func_get_args(), true));
+			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));
 		}
 	}
 
@@ -127,14 +132,14 @@ class Thumbnail
 			if (isset($this->image_meta[$crop_selector]))
 				$this->crop_mode = self::CROP_MODE_BOUNDARY;
 
-			// If the original image's aspect ratio is much wider, take a slice instead.
-			if ($this->image->ratio() > $this->ratio())
-				$this->crop_mode = self::CROP_MODE_SLICE_CENTRE;
-
 			// We won't be cropping if the thumbnail is proportional to its original.
 			elseif (abs($this->ratio() - $this->image->ratio()) <= 0.025)
 				$this->crop_mode = self::CROP_MODE_NONE;
 
+			// If the original image's aspect ratio is much wider, take a slice instead.
+			elseif ($this->image->ratio() > $this->ratio())
+				$this->crop_mode = self::CROP_MODE_SLICE_CENTRE;
+
 			// Slice from the top?
 			elseif ($crop === 'top' || $crop === 'ct')
 				$this->crop_mode = self::CROP_MODE_SLICE_TOP;