Yes, you can, but maybe you will be interested in using Fast Watermark. With this free program you can add watermark to images much easier. You can read the review here:
i use Batch Watermark Creator. i like it because if I am only watermarking and resizing, I can do the entire folder at once. Saves tons of time. find it here: http://www.easy-tools.net/batch-watermark/index.html