Working with file Attachments Working with File Attachments Computer files come in two basic flavors - text and binary. No special characters, no variety of fonts or font sizes, no bold or underscored text, no graphics, and no special formatting.
Email messages are a good example of a text file.
Binary files , on the other hand combine specific computer code along with the basic text which tells a program to display the other features and functions mentioned above. Word processed documents, spreadsheets, executable programs, and any file which contains any elements beyond basic text are all binary format files. That's why, for example, you can't paste a spreadsheet into the body of an email message. The receiving email program, then, must recognize that part of the incoming text was once a file, and must re-convert that portion back into it's original binary file format. MIME is the most common and arguably the best protocol to use.