Merge pull request #2328 from samdoidge/develop

adding thumb_marker to image_lib->clear()
diff --git a/system/libraries/Image_lib.php b/system/libraries/Image_lib.php
index 0cec43f..b6a11a3 100644
--- a/system/libraries/Image_lib.php
+++ b/system/libraries/Image_lib.php
@@ -388,7 +388,7 @@
 	 */
 	public function clear()
 	{
-		$props = array('library_path', 'source_image', 'new_image', 'width', 'height', 'rotation_angle', 'x_axis', 'y_axis', 'wm_text', 'wm_overlay_path', 'wm_font_path', 'wm_shadow_color', 'source_folder', 'dest_folder', 'mime_type', 'orig_width', 'orig_height', 'image_type', 'size_str', 'full_src_path', 'full_dst_path');
+		$props = array('thumb_marker', 'library_path', 'source_image', 'new_image', 'width', 'height', 'rotation_angle', 'x_axis', 'y_axis', 'wm_text', 'wm_overlay_path', 'wm_font_path', 'wm_shadow_color', 'source_folder', 'dest_folder', 'mime_type', 'orig_width', 'orig_height', 'image_type', 'size_str', 'full_src_path', 'full_dst_path');
 
 		foreach ($props as $val)
 		{