Why is a palette image not supported by WebP?
WebP is a modern image format developed by Google that provides superior image compression and quality compared to older formats like JPEG and PNG. However, WebP has some limitations and one of them is its lack of support for palette images.
A palette image, also known as an indexed image, is an image that uses a limited set of colors from a predefined color palette. Instead of storing the pixel values for each individual color, palette images store an index value that corresponds to a specific color in the palette. This allows for more efficient compression and smaller file sizes.
Unfortunately, WebP does not support palette images because it uses a different compression algorithm called VP8/VP9. These algorithms are designed to work efficiently with true-color images that have millions of different colors, rather than indexed images with a limited set of colors.
Example:
Let’s consider an example where we have a palette image with only 16 colors:
In this image, each pixel is represented by a single index value from the color palette. The actual colors are stored in the palette, and the index values point to the corresponding colors.
If we try to convert this palette image to WebP format, the compression algorithm used by WebP may not be able to effectively compress the image. This can result in larger file sizes and potential loss of image quality.
Therefore, it is recommended to use WebP format for true-color images that benefit from its advanced compression algorithms, rather than palette images that are better suited for other image formats like GIF or PNG.