Even today there are many organizations that rely on fax as a required form of communications. Because of this, receiving faxes is a requirement that much still be met. To do this, many organizations utilize fax services either hosted locally or by a third-party. Many of these services will email received faxes to users as a PDF file.

In a normal facsimile transmission, every other scan-line is skipped. This reduces the amount of data that needs to be sent over the relatively slow connection used to send faxes. To account for the missing scan-lines, the aspect ratio of the pixels is 2:1. It is important to recognize this when displaying the image else you will end up displaying the image incorrectly, making it looked squashed.