12 December 2001

When I send e-mails with pictures attached, people complain about the size of the e-mails.

Huge files can cause havoc for small business and home users. A big file can tie up an Internet connection for hours, it could block e-mail from being received and it can knock a small business off the Internet. It is good manners to keep the size of your attachments to a minimum.

Huge e-mails are most irritating for those with dial-up connections. Trying to download a 3Mb e-mail over a 56k connection can easily take 15 minutes. Many e-mail programs will tire of waiting and give a time-out error, many people will find they just cannot clear these messages.

Even if they can clear them, commercial internet providers have limits on how much space your mail can occupy on their server. When you exceed that limit the ISP may reject any more e-mails. This can also happen with company mail servers and a small company system could even crash if the mail is too big.

Avoiding the problem

Pictures are the most common culprit for oversized files. Don't scan in too high a resolution, 150 dpi is usually more than enough. Each time you double the resolution, you quadruple the size of a file.

When sending pictures use the jpg format. JPEG files compress an image substantially and are more likely to be able to read by other computers. Normally you can choose to save the file as a jpg when scanning it or when viewing it in your picture viewer. Never send pictures as bitmaps.

For other files use a utility like Winzip to reduce the size of the files. File compression programs reduce the size of a file by removing the empty space in a file. This works well in some file formats like MS Word or MYOB but JPEGs, Zip file and other tightly compressed file formats actually become bigger when you try to zip them.

Remember a file that takes a minute to send over a cable or corporate network could take hours on a small business or home dial up connection. It could even knock them off the Internet or block their e-mail. That 10Mb video might be funny and that 18Mb baby photo may be cute, but fouling up somebody's Internet connection with it is not going to amuse them. Try to keep your files to less than 500Kb.

Being careful about what you send people is part of e-mail and Internet ettiquette. Keeping attachments to a reasonable size helps everybody get the most from the net. Before you send something, ask yourself whether they need it and is it a reasonable size.