Usually when you have to work on pictures (like resizing, cropping or watermarking them), you take a deep breath and open them in Adobe Photoshop or GIMP or something similar and then go through different menus and toolbars. You can use something easier like the Microsoft Paint application that comes with Windows, but it either saves the pictures in very large files or does not produce pictures of high quality. If you do not want to load these gigantic programs for basic picture editing requirements, then you can use the CoolTweak program which lets you process your images from the right-click context menu.
You can get CoolTweak application from their website. The download is available as a setup installer of around twelve megabytes in size. After the installation, you can right-click on any image file and you would see a new CoolTweak context menu. From this context-menu you can select to resize the image, resize it quickly to a specific size (for example 900px, 1600px), add a watermark to it, share it to facebook, twitter, Picasa, Flickr or 500px.com.
If you choose to resize or watermark you images, you are shown a wizard that guides through the process with multiple options. During this process you can choose to move, rename or overwrite your images, choose picture quality, preserve file properties (EXIF data) etc.
You can also edit this right-click context menu to suit your requirements. To edit this menu, you have to select Open Editor from the context menu itself. This would open the editor for the menu where you can add or remove actions from the CoolTweak context-menu. The Live actions are actions which interact with users, while other actions just carry out the tasks in the background.
CoolTweak is a right-click image processor that can be used to quickly resize or watermark multiple pictures in one go. Although the intention of the software is to be helpful, but the whole user interface is very much bloated and a tiny bit inconvenient at times.
You can download CoolTweak from http://www.cooltweak.com/.