Graphic Tips &
Techniques
Graphics on a Web site can add a lot to the experience of your pages.But, the indiscriminate use of graphics, no matter how cool, will only antagonize viewers to the point that they will switch off the automatic graphics download in their browser and all your efforts at designing an exciting Web page will be lost.
Graphic Tips & Techniques
- Don’t antagonize the viewer
- A full screen of plain text data = 1000 bytes (1K)
- This little icon takes nearly 8K
- Load graphics quickly by interlacing, caching and keeping file sizes compact
- Access (caching) can be achieved by preloading graphics on a previous page. These graphics may be hidden by setting their size to 1.
- Remember that many viewers have their computers set to view only 256 colors.
- Netscape and Internet Explorer use the same 216 colors although their palettes are different.
Return to top of page or scroll down for more Graphics Tips.
Graphic Formats
- GIF and JPEG are the two most common graphic file formats on the Web
- GIF images are NOT limited to 8-bit (256 colors) but virtually all are
- Contrary to popular belief and widespread implementation, the GIF89a spec is not limited to 256 colors
- Itsagif software from Pedagoguery Software http://www.peda.com creates GIFs with 525 or more colors and multiple transparent colors!
- This GIFs will not be as small as 256 color GIFs
- Not all applications have correctly implemented the GIF89 format so images may not display in all applications
- JPEG image files can have true color (16 million colors) or less
- Take a large graphic and break it into smaller sections that when placed in a table on the page give the illusion of a single graphic.
- Use ALT tags to place text where the graphic will appear to explain the image.
- Interlaced GIF and Progressive JPEG formats display a blurry version of the image slowly coming into focus during subsequent passes.
Return to top of page or scroll down for more Graphics Tips.
JPEG Tricks
- Photos are often saved in JPEG format to preserve accurate colors.
- The JPEG file format discards unneeded detail when saving and compressing. Remember to save an uncompressed version of the image for future editing
- Use a utility program when saving an image in JPEG to view the quality
Return to top of page or scroll down for more Graphics Tips.
GIF Tricks
- Optimize palettes
- Reduce colors to even less than 256
- To do this in Photoshop, from the Mode menu, open Indexed, click on 4-bit Adaptive and then on OK. Was your image destroyed? Select Undo, and try again, this time using 6 bits depth.
- If you’re using a flat-color image, such as a simple two or three color chart, you might get away with an even lower bit depth.
- Reset your display set from true color to 256 colors and do a reality check before publishing graphics to the Web.
- For more information, visit the PowerPoint demo titled Using and Manipulating Digital Images
Return to top of page or scroll down for more Graphics Tips.
Utilities for GIF/JPEG compression
Return to top of page.
 |
 |
 |
 |
 |
||||
 |
 |
 |
 |
|||||