Introduction

The Web has developed from an almost pure text environment to a multimedia platform that contains a variety of content. Presenting content in a pleasing way involves producing graphical elements. Thus the Web has turned into a visually oriented medium and graphics and images are essential.

Before we start creating graphics we need to talk about the different graphic formats that we will encounter during this tutorial and on the Web.

Graphic formats

The most common graphic formats on the Web are GIF and JPEG. Both of the formats have different strengths and are used accordingly. A newer format is PNG, which probably will replace the GIF format in the near future.

Let's take a closer look at these different formats:

GIF - Graphics Interchange Format

GIF is usually pronunced "djif" and is the most common format on the Web. Files with a .gif file extension are images in GIF format. The format uses LZW compression, which is an algorithm that allows for more information to be packed into a single file.

The usual compression factor for GIF images is 4:1, and all of the graphical data is restored upon decompression. Therefore GIF is called a lossless format. The latest version of GIF [89a, 1989] allows for multiple frames of images to be stored in a single file and for interlaced loading. These files are called animated GIF images.

A GIF image can contain up to 256 different colors, which is also called 8-bit color depth. All colors are stored in a palette and restored upon decompression. The file size depends on the number of colors and the size of the graphic.

JPEG

JPEG takes its name from the group that developed the standard, the Joint Photographic Experts Group. It is usually pronounced 'jay-peg" The file extension is .jpg or sometimes .jpeg .

The JPEG image format employs up to 29 different compression algorithms to store images. The compression of the data sometimes reaches 50:1, but also can bring a considerable loss of image quality. Sharp edges and straight lines usually get blurred in the compression process. JPEG images may be True Color images (16.7 Mill. colors) but the number of shades is reduced by the compression.

PNG - Portable Network Graphics

PNG is the newest format and was developed because the GIF format includes a compression algorithm that is patented by Unisys. Software makers need to obtain a license from Unisys to create software that exports GIF files.

PNG was implemented in a way that software makers could extend the information contained in the files. An extended PNG format is the native Fireworks format. While the standard PNG format is raster based only (i.e. a real image format), Fireworks PNG also contains vector-based information.

No matter which format you select, Fireworks will optimize the image file and offers multiple ways for the user to select the file type and set the optimization settings.