CPT files are created with Corel Photo-Paint, a raster graphics editor created and sold by the Canadian Corel Corporation headquartered in Ottawa. The application is part of the CorelDRAW Graphics Suite. The latest version of the suite (X6) was released in March 2012 and runs only on Microsoft Windows.

The CPT file format is proprietary (there is no CPT file format specification publicly available) and it's used by Corel Photo-Paint as the default format for saving images. It can also store image information such as layers/objects, transparency settings, color profiles, effect filters, alpha channels, etc.

CPT files are mostly used for saving edited photos before exporting them to more common image formats like PNG, BMP or JPG.

How to open CPT files

Since CPT is a proprietary format, CPT files can be opened with a limited number of applications. However, once opened in Corel Photo-Paint they can be exported to other non-proprietary image formats compatible with a larger number of programs.