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Beginner Tip:
Graphics And The AOL Browser
by Larisa Thomason,
Senior Web Analyst,
NetMechanic, Inc.
Since much of AOL's browser is based on Internet Explorer, webmasters often assume that a site that looks fine in Explorer will also display correctly in AOL. Well, that's not always the case. Graphic images may display in unexpected - and unwanted ways. Learn how to keep AOL's compression algorithm from squeezing your images.
Compression Saves Time And Space
AOL uses graphics compression software to speed up delivery of Web pages and save storage space on its servers. The system works in conjunction with AOL's caching system that we discussed briefly in our March 2001 newsletter article. When a file enters AOL's caching system, the system sends graphics and multimedia files through its compression manager on the AOL system network.
Compressed files load more quickly. Since most AOL members access the Internet through dial-up connections, image caching and compression make their experience more enjoyable. Everyone likes fast loading pages, but dial-up users are particularly grateful.
There's a benefit for AOL too. The compressed files save bandwidth and take up less space on the proxy servers. With more than 30 million members accessing Web pages, AOL saves a considerable amount of storage space by using a compression utility.
The Effects Of Compression
Unfortunately, there are other aspects of AOL's compression software that aren't quite as positive for the end user.
- Graphic images may be blurry after they're compressed. Compression software takes image files and converts them into a proprietary format from Johnson-Grace called .ART. Usually, images hold up well after they're converted, but extremely complex images with lots of color, shading, or minute details may not render perfectly.
- Large background images saved in JPEG format may tile when viewed with AOL's browser. The Johnson-Grace software algorithm scales down JPEG images that are 640 pixels wide or larger. The large image that should fill up your visitor's screen may instead tile unattractively.
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If you're having this problem, try saving your JPEG image as a GIF using your favorite graphics software or image optimization program. The compression software doesn't scale down images in GIF format. Alternatively, save the image as a progressive 3-pass JPEG. The Johnson-Grace software version that AOL is using now doesn't recognize that format. Try both methods to see which looks the best.
Keep Your Graphics Clean On AOL
It isn't widely known, but AOL visitors can turn compression off in their browsers. That's the easiest solution for webmasters, but don't expect it to happen. Visitors generally aren't willing to change their system settings in any way just to view your site.
Instead, follow this simple checklist to make sure that your graphics display correctly.
- Use the correct format. AOL compression software recognizes BMP, GIF, JPEG, and some progressive JPEG formats. You may have to experiment a little and change image formats to get the best effect. If you don't want your images compressed at all, save them in another format, such as a progressive 3-pass JPEG. But remember to always keep close watch on image file size and optimize your images to reduce file size whenever possible.
- Avoid headers in images. Some graphics programs like Adobe Photoshop and PhotoDeluxe add additional information to the headers in image files. That extra information sometimes causes the JPEG images to display with extra bands of color or black blocks inside the image. If you're having this problem, load the image back into your graphics package and save it without using the option that gives you thumbnail previews.
- Control JPEG size. Because the software scales down JPEG images that are wider than 640 pixels, keep a careful watch on your image size to avoid distortions or tiling.
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The only sure way to see if your graphics will be affected by AOL's compression software is to check it yourself. That method requires you to either become an AOL member (if you aren't) or talk a friend who is into letting you use his computer as your own private testing lab.
But an easier way is to test your pages with Browser Photo. In a single report, you can see how your Web page displays in 14 different browser, browser version, and operating system combinations. You'll save time, money, and wear and tear on your friendships!
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