Why zip a file?
Zipping a file creates a compressed version of the file that is considerably smaller than the original file. The zipped version of the file has a .zip file extension. For example, if you zip a Microsoft Office Word document called Pneumonia.doc that is 6.5 megabytes (MB) in size, the file created, Pneumonia.zip, is reduced to 2.5 MB. File types that are reduced the most as a result of zipping are text-oriented file types, such as .txt, .doc, .xls, and graphics files that use non-compressed file types such as .bmp. Some graphic files, such as .jpg and .gif files, already use compression; therefore, the file size is reduced very little by zipping. Also, a Word document that is full of graphics files does not get reduced as much as a document that is mostly text.
Unzip a file
To unzip a file, right-click the file, such as Pneumonia.zip, and then click Extract on the shortcut menu.