In this format, you can save images that are shot on Sony (Minolta) cameras and some digital SLR cameras. MRW images are stored in uncompressed RAW form, and they contain more detail than compressed images. This format allows you to edit the white balance, exposure, brightness, and other elements losslessly.
PNG is a raster graphic data storage format that uses lossless compression algorithm to Deflate. PNG was created as a free format to replace GIF. PNG supports three main types of raster images: grayscale image, a color indexed image and the color image. PNG format stores graphical information in a compressed form.