PEF is a highly specialized raster image format. Created by the manufacturer of Pentax cameras for storing digital images taken by these devices. The name is an abbreviation for Pentax Electronic File. PEF files are digital photographs (RAW) without any compression, color editing or distortion. Data taken directly from the Pentax camera sensor. This format is also used by some Samsung cameras. At the same time, PEF format files are not compatible with image viewers, they cannot be printed and edited in graphic editors, they are not available for posting online. All this is possible only when converting to another format.
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.