Over 60% of the file size of the average web page is taken up by graphics and multimedia. So graphics optimization is an important step in optimizing web page speed. At an alarming frequency, we have seen large PNG24 and unoptimized JPEGs used on the Web. Large PNG24s should be optimized for file size or converted to PNG8s. This article shows how to optimize PNG files effectively by minimizing their color palettes, and using alpha transparency intelligently.
Drop shadows add impact to web graphics, but they also impact file size. You can minimize the resulting file size of palette-based images such as GIFs and PNGs by reducing the complexity of drop shadows. This article shows how to create optimized drop-shadows in Photoshop to minimize the size of web graphics.
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.
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.