"A good marker to remember is to keep the total page weight in terms of file size somewhere between 30-60 kilobytes," said Ninness. If the page has an aggregate size of greater than 60 kilobytes, then the user is waiting longer than 60 seconds to download it.

Users get impatient after about 30 seconds, so even if you've built a 70-kilobyte page and the user is using a 28.8 modem, it will still take longer than 30 seconds to download.

A good way to keep track of the pixel size of your work, Ninness said, is to switch your measurement palette to points (there are 72.25 points per inch and 72 pixels per inch). That way, you can lay out the page at 590-by-325 points and it will work on an average monitor.

He went on to explain that dithering is "using the 256 colors that you have for the millions that you don't." He said it's OK for photographs to dither color, but solid colors -- like line art, logos, icons and buttons -- shouldn't dither. The way to avoid dithering is to use the 216-color web palette (it's available at http://www.lynda.com/).

Ninness emphasized trying to speed things along for the end user.

"Every image should have width, height and alt attributes assigned to the image tag," said Ninness. "The width and height attributes make for more efficient downloading of a page."

In addition to the tag attributes, Ninness suggested that designers use graphics repeatedly.

"If you use a previously viewed graphic again on a different page, or even on the same page, the browser says to itself, 'Hey, wait a minute. I've already seen this graphic. As a matter of fact I've already copied this to your hard drive. I don't need to download this from the server again, I can just show you the copy I've already got.'"

Ninness said, "This is what they mean when all those people tell you smugly, 'Oh, yeah, your graphic has been cached.'"

-- dmc

From THE COLE PAPERS, November 1997, Copyright © 1997, All Rights Reserved.