I'm not attempting to be facetious, but tell your users that you do not support any version of Netscape below 6.2. This sounds like a number of issues we've run into where I work. We do a web app that uses a ton of stuff, including <div> and the like. If you can't make it work, don't support it. You didn't write the browser, you can't make the browser better. The people who developed it did - it's called free upgrades.

Of course, if you can't (for whatever reason), it sounds like you're going to have to detect that it's Netscape 4.75 and render the image some other way.

(I'm assuming you know what you're doing re: CGI and image-rendering.)

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.