To protect your original work, adding WP Manga Nulled watermark is a choice. This plugin will add a (image) watermark to every images when you upload a chapter.
You can configure position of the watermark any any point and upload your image WP Manga Free Download watermark, is that simple?
Please note that it works with new uploaded chapters only. It doesn’t auto add watermarks to existing chapters
Demo: https://mangabooth.com/product/wp-manga-watermark/