Web Design in a Nutshell, 3rd Edition

Keep File Sizes Small

Here is the single most important guideline a web designer can follow:

Keep the file sizes of your graphics as small as possible!

The nature of publishing over a network creates a new responsibility for designers to be sensitive to the issue of download times. In fact, many corporate clients will set a kilobyte limit (sometimes referred to as the K-limit ) that the sum of all the files on a page cannot exceed. Even if keeping files small is not a priority for you, it may be for your clients.

Detailed strategies for minimizing graphic file size for each file format appear in the format-specific chapters. Here are a few general strategies that help graphics load more quickly:

Limit dimensions

Though fairly obvious, the easiest way to keep file size down is to limit the dimensions of the graphic itself. There aren’t any magic numbers; just don’t make graphics any larger than they need to be.

Design for the compression scheme

One of the key ways to make your files as small as possible is to take full advantage of their compression schemes. For instance, because you know that GIF compression likes flat colors, don’t design GIF images with gradient color blends when a flat color will suffice. And Because JPEGs like soft transitions and no hard edges, you can try strategically blurring images that will be saved in JPEG format. These techniques are discussed further in the “Optimizing” sections of the GIF and JPEG chapters.

Reuse and recycle

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