Optimizing the Palette in GIFs and PNGs

As you know from Topic 27, GIF and PNG files have a built-in palette of up to 256 colors. The more colors in the palette, the heavier the image file. If your GIF or PNG image needs all 256 colors, then so be it. However, most GIFs and PNGs can stand to lose some color slots without affecting image quality too noticeably.

GEEKSPEAK

Antialiasing is a technique for creating the appearance of smooth, flowing curves by inserting subtly blended pixels along a curved edge.

Watch out for images that contain round or curved shapes. These images often make use of a technique called antialiasing, which creates the illusion of smoothness by inserting subtly blended pixels along the curved edge. Antialiasing minimizes the naturally blocky appearance of pixels, which are square-shaped, and tricks the eye into seeing graceful, flowing curves. Each blended shade requires a slot in the palette of a GIF or PNG. Cutting too many colors from the palette reduces the effectiveness of antialiasing.