The standard feature for uploading images in the wiki is only for single uploads. But this is very laborious, if you need lots of pictures, which should be available in the wiki. A small and free program solves this problem and helps for this task with an multiple upload feature – the “Commonist”.
The tool was developed as an upload client primarily for Wikimedia commons. But you can configure it with the path to your wiki(s). The images will be uploaded in the wiki you defined automatically.
By the way, you can use Commonist for both – BlueSpice and MediaWiki!