Adding Watermark on product photo of 2,000 listings.

Hello. We have a running E-commerce store with over 2,000 products in Store. [login to view URL] All product photo have been uploaded on the website but there are no watermark on the photo. So many internet surfer are using our products photo without our permission. So now we would like to add watermark on every listing and photo on the website. We need someone to help us add watermark, "[login to view URL]" on every product photo. We are using bigcommerce shopping cart. Please bid on my project and let me know about how fast you can handle this project and what is the method of doing it? We need the photo quality to be the same. Happy bidding.