CoolTweak is a free application for Windows machines that lets you batch resize and watermark images. It integrates directly in the right click menu of windows explorer and is then always accessible.
CoolTweak offers integrated sharing with social nextworks like Facebook, Twitter, Flickr, Google+ and 500px. You can create customized actions for resizing, watermarking and sharing as well.
CoolTweak was updated to version 2.0 in October 2013 and remains a free program. Learn more on CoolTweak’s website.