Online image tagging system is developed software that allows users of the Gordon Center for Subsurface Sensing and Imaging Systems (Gordon-CenSSIS) Image Database to associate detailed metadata with specific regions of images, a process we refer to as "Image Tagging". The process of image tagging involves using the image tagging interface to draw an outline around a region of interest in an image. Once the area has been selected, a label can be placed on it and additional metadata can be associated with it. The metadata can contain custom XML tags in addition to the standard XML elements that the general tag data is stored in. Eventually, users will be able to query these tags via the database interface. The benefit of having this additional metadata available is that it provides a finer level of detail for querying. It allows users to find more specific features in images than the coarser metadata originally available. Image Tagging improves the quality, consistency, and usefulness of the data in the database.