Doc (an abbreviation of document) is a file extension for word processing documents; it is associated mainly with Microsoft and their Microsoft Word application. Historically, it was used for documentation in plain-text format, particularly of programs or computer hardware, on a wide range of operating systems. Almost everyone would have used the doc file format, whenever you write a letter, do some work or generally write on your PC you will use the doc file format. It was in the 1990s that Microsoft chose the doc extension for their proprietary Microsoft Word processing formats. As PC technology has grown the original uses for the extension have become less important and have largely disappeared from the PC world.
Early versions of the doc file format contained mostly formatted text, however development of the format has allowed doc files to contain a wide variety of embedded objects such as charts and tables from other applications as well as media such as videos, images, sounds and diagrams. doc files can also contain mail merge information, which allows a word-processed template to be used in conjunction with a spreadsheet or database.
AbiWord Apple Pages AppleWorks KWord Microsoft Word StarOffice
PNG pronounced ping is a format for storing bitmapped (raster) images on computers. It was created originally to replace the GIF file format when it was announced that the companies who created the GIF format wanted royalties. PNG uses indexed colors and lossless compression (like a .GIF file), but without those copyright limitations; it cannot be animated like a GIF image.
PNG images are in many ways better than .GIF as they also include an 8-bit transparency channel, which allows the colors in the image to fade from opaque to transparent; GIF images only support fully opaque or fully transparent pixels. PNG supports palettes of 24-bit RGB colors, RGB images or greyscale or RGB images. PNG was intended to be able to transfer images on the Internet, not professional graphics, and so does not support other colour spaces (such as CMYK).
Apple Preview Corel Paint Shop Pro GIMP - The GNU Image Manipulation Program (LINUX) Microsoft Windows Photo Gallery Viewer Safari