There is no such thing as a .org file. .org is a top level domain extension like .com, .gov, .edu, and .net. It is used for website access and browsing the web, not saving files.
an image file
picture file.
picture file.
There is only one file that the name ends with GIF. The only file that ends with GIF is saving a picture.
Images.
system file
A Graphics Interchange Format file is a picture format file.
.gif is a picture format they can be either a animated picture or a still
The sys file extension was developed by Microsoft. Most files that end with sys are system data files and are not meant to be viewed by the users.
Graphic Interchange Format. It will be a picture of some kind. Here is a site that explains it: http://www.webopedia.com/TERM/G/GIF.html Image files, generally from web sources, they may be transparent / animated.
It varies by the extension. A compressed file ends in an underscore _ A hidden file ends with a dollar sign $ A regular extension usually ends in a letter (.exe, .zip, .rar, .txt, etc)