Optimizing Images for Web and Email

Optimizing images for Web and Netscape Email

Overview
Graphic images, just like word processing and spreadsheet documents, are stored as digital files. Image files can be quite large, depending on such factors as:

File format

JPG and GIF files were developed and refined with the Internet and the moving of data from point A to point B in mind. Other formats like BMP were not and it shows in the file size.

Actual image dimensions

An 8x10 image will likely be a bigger file than a 4x5 image in the same format, all other settings choices being equal. That again is actual dimensions-- the size the image would print at.
Within a web page or an email you can set the image to be displayed in a smaller height & width but that doesn't affect the file size.

Resolution, complexity, and other appearance quality issues.

Larger file sizes will result from higher resolution, more distinct colors, and other factors that add data and instructions to the file.

Optimizing for the web is the process of taking away some of the data that makes up an image in such a way that the file size is minimized but the appearance stays roughly the same. Keep in mind that images are going to be viewed and printed on monitors and printers that have limits in resolution and a photo quality image will be wasted on them. Many graphics software programs, such as Macromedia Fireworks, have features that will automate the web optimization process, rendering an image that will be no more complex than a monitor will appreciate while minimizing the download time.

To optimize an image before inserting it in a web page or email: Launch Fireworks (Start Menu\|NAL\|Internet\|Web Authoring or Start Menu\|NAL\|Graphics ) From the Fireworks File Menu, select Open Use the dialog window to locate and open your existing image file. You may wish to select "All Files" under Files of Type:.

With the image in view, click on the File Menu and select Export Wizard. The first of several Export windows will appear. On this window, you have the option of selecting a target export file size (lower left corner). If you leave this unchecked (recommended), you will still be able to adjust the file size later in the process. Click the Continue button.

On the second window, be sure the radio button for The Web is checked. Click the Continue button.

The analysis results window will appear. While the program may make some recommendations on the best export format, the next window will allow you to view your options side by side. Generally speaking, photos look best in JPEG while line drawings are rendered best in GIF. GIF should also be used when you have an image with a transparent background. Click Exit.

The Export Preview window will appear, likely showing your image in both JPEG and GIF formats. The file size and other image data show either above the JPEG version or below the GIF version. Adjusting Quality Level: The main choice to make is quality versus file size. The higher the quality the larger the file size. You can adjust the quality up and down until you determine the lowest acceptable quality level. While on the Options tab, click once on the image that currently looks best to you. Adjust the quality setting by left-clicking the mouse on the down arrow next to the Quality function. This pops up a slide control. Slide up for high quality and down for low. Notice that as you adjust the quality, the image preview will reflect it. Notice also that the image data will update to show the new file size, quality level, and download time. Other Options: This toolbar will allow you to change the dimensions of the image by cropping it down to the main subject. Click the image size menu so you can see the entire image then select the crop tool. This will place a frame with handles around the image; use the handles to adjust the frame-- anything outside the frame will be trimmed away. When satisfied with your choices, click the Export button.