With the average web page made up of more than 50 objects (Krishnamurthy and Wills 2006), object overhead now dominates the latency of most web pages (Yuan 2005). Following the recommendation of the HTTP 1.1 specification, browsers typically default to two simultaneous threads per hostname. As the number of HTTP requests required by a web page increase from 3 to 23, the actual download time of objects as a percentage of total page download time drops from 50% to only 14% (see Figure 1).
Graphic optimization
CSS Sprites: How Yahoo.com and AOL.com Improve Web Performance
CSS sprites group multiple images into one composite image and display them using CSS background positioning. You can save a significant amount of HTTP requests by consolidating your images into one or more composite sprites and using CSS to selectively display parts of the sprite within your web page. Now that the major browsers have evolved enough to support CSS backgrounds and positioning, more sites are adopting this performance technique. In fact, some of the busiest sites on the Web use CSS sprites to save HTTP requests. In this article we’ll expand on our mini-CSS sprite example (mono-image CSS rollovers) to show how Yahoo! and AOL use sprites to improve performance.
Mono-Image CSS Rollovers
CSS is traditionally used to create rollover effects with two or more images for menus and other elements. Menus can use on, off, or visited images to signify the state of the menu. Typically menus are created using multiple background images, however. The problem with this method is that it doubles the necessary HTTP requests and can cause flickering problems when the “off” image is not preloaded. A better way is to combine the on and off state images into one mini-sprite and switch the background position on rollover (see Figure 1).
Minimize Noise to Maximize Graphic and Video Compression – tips to optimize web videos and images
Multimedia compression can be thought of as a war against unnecessary noise. Noise is the unwanted random dot pattern overlaid on videos and graphics when electronic noise is present, due in part to the random motion of electrons. Noise creeps into images, both still and motion, with the more lossy steps you take when manipulating images. These random dot patterns, or “snow,” prevent compression algorithms from working optimally, increasing file sizes. By minimizing the noise in your original images and videos, you can gain the maximum amount of compression when optimizing images and videos destined for the Web.
Update: Pro Ball Head Review – compares ball heads to give sharper photos & solid video support
Ball heads provide stability and mobility for photographers on the go. Combined with a stable tripod a solid ball head can help dampen out vibration for sharper photographs, especially for larger enlargements. Sharper photographs and videos make for smaller, higher quality multimedia for the Web. This article reviews some professional ball head options and looks at vibration testing with a laser vibrometer.
Replace GIF with PNG Images – portable network graphics images compress more efficiently than gifs
The Portable Network Graphics (PNG) format is designed to be a more efficient, flexible, and patent-free replacement for GIFs. PNG is designed to store a single bitmapped image to display over computer networks (1). PNG was created in 1995 as a response to Unisys’ enforcement of their patent on the LZW compression algorithm used in GIFs. While Unisys’ patent has expired, the reasons for switching to PNGs from GIFs remain (2). By replacing your GIFs with PNGs you can speed up your web pages and save bandwidth.
Automated Color Harmony Tools – color harmonization using automatic color theory tools to optimize color palettes
Harmonic colors are color combinations that have special internal relationships that are aesthetically pleasing to the human eye. Professional web designers experienced in color theory can create color palettes that evoke different moods, appropriate to the product or service being sold.
Don’t Let the Graphics Grinch Steal Your Christmas Bonus
By now most web developers, advertisers and executives know the mantra: slow web sites lose money. But what they may not know is how much of those losses are due to the single biggest common source of
site bloat: overweight graphics. So this season we have a little gift to help you remember how important it is to fix this problem on your site right away (unless you really want to send your business to your
competition). Herewith is this year’s mangling of Clement Moore’s “A Visit From St. Nicholas” (a proud tradition) and a sincere wish for a happy, peaceful and prosperous New Year to you and your loved ones.
With permission from our poetry mangler in residence, Bob Peyser….
Combine Images to Save HTTP Requests – use imagemaps on combined images with ismap usemap tutorial
One byproduct of automated image-slicing software is the plethora of images now populating the Web. As early as 2002 (King 2003) the average web page had over 24 embedded objects, with over half the total page size consisting of images. Today when we analyze web pages we commonly see 50 to 60 images per web page. The more round trip server requests you require in your pages, the longer and more indeterminate your load time becomes. One way to reduce the number of HTTP requests is to combine adjacent images into one composite image and optionally imagemap the links to different areas. This tutorial shows both client and server side techniques you can use to save precious HTTP requests and speed up your site.
CSS Overlays: Using CSS Positioning to Overlay Web Objects – css layout tutorial
An overlay is when one web object overlaps another. Overlays are often used to highlight or draw attention to important items on websites to raise conversion rates. This article shows how use CSS positioning to avoid slicing and dicing your overlays and assembling with tables. Along the way we’ll look at the workarounds we used to make the technique work with different browsers (most importantly IE5.x Mac and Safari).