Watermark Tool is the free online watermarking application that allows you to quickly and easily protect your images with a visible watermark. There are other free application available for watermarking, but this online service offers a good job in watermarking with variety of options to personalize your images including text size, color, and position. Watermarking Tool does not actually host any images, it will only watermark your images.
The watermarking process is also very simple, select the image from your computer using the browse option. Then you can customize the watermark by adding your text, font, color, position etc.
Once you are ready to watermark, click on the generate button. Watermark Tool can watermark only .jpeg and .gif images. Maximum file size supported is 100kb, so this is more suitable for images intended to be published online.