diff --git a/post.php b/post.php
index 0e46e80d..02ccd53e 100644
--- a/post.php
+++ b/post.php
@@ -1407,7 +1407,7 @@ function handle_post(Context $ctx)
                     $file['extension'] == ($config['thumb_ext'] ? $config['thumb_ext'] : $file['extension'])
                 ) {
                     // Copy, because there's nothing to resize
-                    coopy($file['tmp_name'], $file['thumb']);
+                    copy($file['tmp_name'], $file['thumb']);
 
                     $file['thumbwidth'] = $image->size->width;
                     $file['thumbheight'] = $image->size->height;