WhatAmark is a watermark tool and photo compressor

http://neonway.org/whatamark/
If you are looking to protect your photos from unauthorized use with watermarks, try WhatAMark ! This app allows you to create an image or text overlay , multiple watermarks on the same picture, and you can even work on large batches of pictures, watermarking them all simultaneously! Want to add a text logo? Combine or superimpose different pictures? WhatAMark makes it really easy!