Optimization options for Images and Animated GIFs

GIF is the standard format for compressing images with flat color and crisp detail, such as line art, logos, or illustrations with type. Like the GIF format, the PNG‑8 format efficiently compresses solid areas of color while preserving sharp detail.

PNG‑8 and GIF files support 8‑bit color, so they can display up to 256 colors. The process of determining which colors to use is called indexing, so images in GIF and PNG‑8 formats are sometimes called indexed color images. To convert an image to indexed color, a color lookup table is built to store and index the colors in the image. If a color in the original image does not appear in the color lookup table, the application either chooses the closest color in the table or simulates the color using a combination of available colors.

In addition to the following options, you can also adjust the number of colors in the image’s color table.