diff --git a/post.php b/post.php
index f504778a..fea3553f 100644
--- a/post.php
+++ b/post.php
@@ -1032,7 +1032,7 @@ if (isset($_POST['delete'])) {
 		} else {
 			if ($file['extension'] == "pdf" && $config['pdf_file_thumbnail']){
 				$path = $file['thumb'];
-				$error = shell_exec_error( 'convert -thumbnail x300 -background white -alpha remove ' .
+				$error = shell_exec_error( 'convert -size '.$config['thumb_width'].'x'.$config['thumb_height'].' -thumbnail '.$config['thumb_width'].'x'.$config['thumb_height'].' -background white -alpha remove ' .
 				escapeshellarg($file['tmp_name']. '[0]') . ' ' .
 				escapeshellarg($file['thumb']));