CRW is a highly specialized graphic file format developed by the manufacturer of the famous Canon cameras. It is designed to record “raw” images captured by different models of a digital camera Canon. In its characteristics, it is very similar to another proprietary format of this developer - CR2. The main advantage of the CWR format is the preservation of the quality of the digital image as it comes from the camera matrix. The format also contains metadata, namely: conditions for photographing and fixing the image, default image processing settings, camera model.
PNG is a raster image format developed by PNG Development Group. The name PNG is an abbreviation for Portable Network Graphic. This image format is used primarily on the Internet for posting on web pages, since PNG files use Deflate compression without losing quality. The development of this format was undertaken in order to replace the GIF format, to which there were many complaints. PNG's image quality and specifications were much better, but unlike GIF, it does not support animation and uses the CMYK palette.