Windows 7 -- About File Extensions
File extensions are the suffix or extension to a file name. They are usually three to four characters long and are placed after a period after the file name.
- My Photo.jpg
- text file.txt
- web page.html
- My drawing.gif
File extensions are important because they tell you what the file is text, image, etc. They are also used by your computer to remember which program to open those certain files in.
Sometimes Windows 7 will have the default settings to not display these important extensions. If you find you are not able to view extensions by looking at your files, it is strongly advised that you change your settings to display them. For instructions on how to display extensions view this page.
For instructions on how to change which programs open certain extensions view this page.