this is a new format that supports lossless and loss compression quality for images on the Internet. The Google Company developed this format specifically to do work online as quickly and conveniently as possible. The main advantage is that its file size is small compared to other image formats, but similar in image quality.
This format was developed by Apple for storing vector and bitmap images with metadata. It was the main format for the QuickDraw graphics software. PCT supports 32-bit and 24-bit images. At the moment, the format is obsolete and has been superseded by more functional solutions.