Web Design

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D

epending on how the image was created, images you want to use on your Web site can potentially

come in any one of hundreds of formats, but the Web supports only three: GIF, JPEG, and PNG.

Before you can begin working with images on your pages, you need to understand these formats so

that you can choose the one that works best. Each format has specific advantages and disadvantages,

and you will need to evaluate each image to determine the format that works best for it.

Understanding Image Formats

The Formats for the Web

Browsers can natively display images saved in the JPEG, GIF, and PNG

formats. Any other format requires that the browser use a plug-in, so

these three are commonly thought of as the formats the Web supports.

If you have an image in any other format, you will need to convert it

to one of these.

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GIF

JPEG

JPEG is short for Joint Photographic Expert’s Group, the organization

that originally developed the format. The JPEG format supports

millions of colors and is thus best for photographic images. Most

of today’s digital cameras save images as JPEGs by default.

JPEGJPEGJPEG

GIF

Originally developed in the 1980s by CompuServe, the Graphics

Interchange Format has long been a standard on the Internet, even

before the Web. GIFs support a maximum of 256 colors, and today are

primarily used for logos, line art, and buttons. Unlike JPEG, GIFs

support transparency and animation.

GIFGIFGIF

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Supports Up To^256 Colo

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PNG

Developed as an alternative to GIF, the Portable Network Graphics

format combines the best features of the JPEG and GIF formats. Like

JPEG, a PNG can have millions of colors, and like GIF, PNGs can

support transparency.

PNG