Bigger Isn’t Always Better

Posted: May 3rd, 2010
Filed under: IIS & HTTP, Web Speed and Performance
Tags: , , , , ,


Consider your image sizes for better site performance

Graphics and multimedia can take up more than 60% of the total file size of an average web page, so graphics optimization matters. Not only should the size and file type of your images be taken into consideration, but how fresh they are as well.

Image Caching

Minimizing round trips over the Web to revalidate cached items can make a huge difference in browser page load times. Perhaps the most dramatic illustration of this occurs when a user returns to a site for the second time, after an initial browser session. In this case, all page objects will have to be revalidated, each costing valuable fractions of a second and blocking actual new content from using the browser’s available network connections (not to mention consuming bandwidth and server cycles).

Taking Charge of Caching

Effective caching makes more efficient use of bandwidth and server resources to free up availability for new site/app visitors. Regardless of which Web server you use, it is well worth the time to figure out how to manage cache control at the server level. If you use IIS, CacheRight can make this quite easy by providing not only directory but site-wide control of your server cache.

PNG vs. GIF

PNGs were designed to be a superior replacement for the Graphic Interchange Format (GIF). GIFs are limited to 256 colors (8-bit color palette), one level of transparency, and the Lempel-Ziv-Welch (LZW) compression algorithm that was patented by UNISYS. In most cases, PNG files from the same source images are smaller than corresponding GIFs. PNGs use the “deflate” compression algorithm, which is 10 to 30% more efficient than LZW compression.

The folks over at www.websiteoptimization.com have a great article on PNG24 and PNG Optimization you should check out if you’d like to see an example on this study.

Image Compression

A highly configurable compression tool enables an administrator to adjust the trade-off point between processor utilization and compressed resource size by setting the compression level for all resources on the Web site, thereby not wasting CPU cycles on “over-compressing” objects which might compress nearly as tightly with far fewer resources.

This also allows for the selective compression of image files. Many images are already optimized when they are created in an editor such as Illustrator; avoiding the needless recompression of such images is vital. But there still may be JPEG or PNG images that would benefit from compression. Port80’s httpZip provides one of the best solutions for granular management of your Windows IIS Server site compression.

/P80

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