edit

lib/Store/Core.php

@@ -429,6 +429,9 @@ class Core
 	protected function ext()
 	{
 		$this->ext  = $this->ext ? $this->ext : '.' . pathinfo($this->data['file']['name'], PATHINFO_EXTENSION);
+		if ($this->ext == '.') {
+			$this->ext = '.jpg';
+		}
 
 		return $this;
 	}