Choosing a File Format for
Nearly all graphics on the
Internet are either JPEG (Joint Photographic Experts Group) or GIF
(Graphics Interchange Format) format. Other file formats, such as PNG
(Portable Network Graphics) exist, but to be sure that the greatest number
of browsers can display a graphic, choose either JPEG or GIF
Use .jpg files for:
A large number of colors, such as in the millions.
An image with large dimensions.
Use .gif files for:
- Images that contain transparent areas.
- A limited number of colors, such as 256 or less.
- Colors in discrete areas.
- Black and white images.
- A small-size image, such as a button on a site.
- Images in which sharpness and edge clarity are important, such as
line drawings or cartoons.
- Images containing text.
The purpose of the graphic will help determine its size, file format,
style, and appearance. Before you begin to work on a graphic, ask yourself
if the graphic adds something to your site. If the answer is no, don't use
Consider the Total Size of Your Web Page
Although estimates vary, many Web page designers suggest that you keep
the total size of a Web page from 40 KB to 60 KB for most purposes, and
not more than 75 KB.
Use the smallest graphic possible. Remember that the JPEG format can
produce the smallest size file.
Alternatives to Graphics
If your goal in using a graphic is to catch a reader's eye, you can
sometimes accomplish the same purpose in ways that will reduce file size
and download time.
Consider using a solid color that will complement the color of text
on the page, instead of using background images for a Web page.
Consider using spot color in blocks in specific areas of a page to
call attention to a block of text, or to group information.
Consider using different colors in table cells to group information
or highlight specific information.