--- field_slideshow.module.orig	2011-08-30 17:14:54.000000000 +1000
+++ field_slideshow.module	2011-11-30 21:20:26.000000000 +1100
@@ -685,17 +685,27 @@ function theme_field_slideshow($variable
       $image_output = theme('image', $image);
     }
 
-    // Get image sizes and add them the img tag, so height is correctly calctulated by Cycle
-    if (isset($variables['image_style'])) {
-      $image_path = image_style_path($variables['image_style'], $image['path']);
-      // if thumbnail is not generated, do it, so we can get the dimensions
-      if (!file_exists($image_path)) {
-        image_style_create_derivative(image_style_load($variables['image_style']), $image['path'], $image_path);
+    if (strpos($image_output, 'width') && strpos($image_output, 'height')) {
+		preg_match('/width="?(\d+)"?/', $image_output, $match);
+		$width = (isset($match[1])) ? $match[1] : NULL;
+		preg_match('/height="?(\d+)"?/', $image_output, $match);
+		$height = (isset($match[1])) ? $match[1] : NULL;
+	}
+	if (isset($width) && isset($height)) {
+		$image_dims = array($width, $height);
+	} else {
+      // Get image sizes and add them the img tag, so height is correctly calctulated by Cycle
+      if (isset($variables['image_style'])) {
+        $image_path = image_style_path($variables['image_style'], $image['path']);
+        // if thumbnail is not generated, do it, so we can get the dimensions
+        if (!file_exists($image_path)) {
+		    $image_path = image_style_url($variables['image_style'], $image['path']);
+     	}
       }
-    }
-    else $image_path = $image['path'];
-    $image_dims = getimagesize($image_path);
-    $image_output = drupal_substr($image_output, 0, -2) . $image_dims[3] . ' />';
+      else $image_path = $image['path'];
+      $image_dims = getimagesize($image_path);
+      $image_output = drupal_substr($image_output, 0, -2) . $image_dims[3] . ' />';
+	}
     if ($image_dims[0] > $slides_max_width) $slides_max_width = $image_dims[0];
     if ($image_dims[1] > $slides_max_height) $slides_max_height = $image_dims[1];