Programming Web Graphics with Perl and GNU Softwar

Chapter 2. Serving Graphics on the Web

When creating graphics, one should keep in mind that not all web browsers handle all “standard” HTML features in the same way. Specifically, browsers have been known to have their own idiosyncratic interpretations of the ALT attribute, client-side image maps, the USEMAP attribute, GIF89a animation, image spacing attributes, transparency, inline PNG/XBM/Progressive JPEG images, the LOWSRCattribute, borders on image links, alignment tags, and scaling tags.

In short, just about every feature that should have a standard implementation has, at one time or another, had different levels of compliance to the standard on different browsers. As of this writing, the most popular browsers implement the HTML 3.2 standards such that they can be trusted with your exquisitely crafted HTML code. However, be sure to do a little research before making your knockout web page depend on some new or proprietary feature. You may be writing off a significant portion of your potential audience who can’t see it.

The same could be said for external image-viewing plug-ins. Now that we are several years into the Web Revolution, users are spending more time using the Web to get exactly the information they want and less time “surfing” the waves of information overload. Developers are also realizing the ramifications of the time and costs associated with keeping a web site going until Doomsday. If you are thinking about adding critical images (or even non-critical information, ...