This is a vector imaging format used in the CorelDRAW editor. It has a template that can be applied for other designs, including styles, grid parameters, page layout and other parameters. The CDT template allows for the creation of several images in one style without changing the settings in manual mode.
ICO is an image file format that can contains image icons. ICO is used in Microsoft Windows Operating systems to contain the icon files. It typically contains bitmap images. Also ICO files are used in websites as favicon. It supports 24 bit colors images.