aPhoto is a Batch Intuitive Program Makes Text and Image Watermarks
Lenna: Open Source Image Processing Program
Easy to Use Batch Image Editor with Watermark features....
BRIC is a powerful tool for batch image processing.
Add watermark to any image or photo (batch processing available).
View and alter images (batch processing available).
iwatermark is a image watermarking web application.
Batch Watermarker allows you to add logos to many pictures at once