With the advent of an Internet protocol called MIME, Multipurpose Internet Mail Extension, and other types of encoding schemes, you can send formatted documents, photos, sound and video files as attachments to your e-mail messages.
These protocols use a complex mathematical formula to convert files to text and then back to their original form. This conversion process is known as encoding and decoding. If the person to whom you are sending an attachment uses an MIME-compliant or Uuencode e-mail program–and almost all programs do–it automatically detects the attachment, decodes it, and either opens it or prompts the recipient to save the file.
Before Hitting Send
Before you send binary files or formatted documents as attachments, make sure that the person you are sending them to has the ability to open the files. For instance, if you send a spreadsheet created in Excel, the recipient needs that program to view the file. While virtually all modern email systems have the capability to transfer binary files, you may need to save the file in a specific format prior to transmission so that the recipient can open the file with the software they have available on their computer.
By the way, don't confuse encoding a file with encrypting a file. Encoding files adds no security. Anyone with the right decoding software can view it.
How to Do It
The procedure for attaching files varies depending on the type of e-mail program you use. In general, you click an icon, such as a paper clip, located on the toolbar of the program. If you use a Web-based e-mail service like Yahoo! Mail or Gmail, click “Attach” on the toolbar to attach a file. Select the file you want to attach by locating it on your hard drive or external storage device. Once you've selected the file, either its name will appear as part of the e-mail header, or as an icon within the body of your message. Most programs allow you to attach multiple files, but may limit the size of the files. (Many e-mail services won't let you send files larger than 25 Mb.) Once the files are attached, click the Send button and off they go.
For more help, see Step-by-Step: Sending E-mail Attachments.
Frequently Asked Questions
Are there any types of files that shouldn't be sent as attachments?
Certain file types are commonly used to transmit viruses and automatically blocked by leading email service providers as a result. For this reason, you should avoid emailing executable files (.exe for example) and archive files (.zip, .tar, .rar, and so forth).
How can files larger than 25 MB be transmitted?
If you need to send a file that's larger than 25 MB you have two options. First, you could reduce the file size by breaking the file into multiple parts. In the case of a large editable file, this isn't too much of a problem. However, for other file types, this is more problematic. If breaking the file into multiple parts won't work, you'll need to find another way to transmit the file. Your best bet is probably to use a cloud storage solution such as Google Drive or Dropbox. With these services you upload the file to a cloud server and the recipient downloads the file.
What's the difference between encoding and encrypting?
They sound similar, but encoding and encrypting are quite different.
- Encoding is converting any type of data into plain ASCII text. While you wouldn't be able to read encoded information yourself, any decoding program will make short work of encoded content. In other words, encoding does not protect content from prying eyes.
- Encrypting, on the other hand, transforms data into a format that can only be easily decrypted by the intended recipient.
While both encoding and encrypting deal with the conversion of data from one format into another, encoding is focused on usability while encryption is focused on protection.