Pixel Graphics Design Tips

The GIF format uses a lossless compression algorithm meaning that the image is compressed with no quality loss. However, the GIF format supports only 8-bit colour (256 colours) making it ideal for line art images containing few colours or artwork that has large areas of the same colour. It also supports some useful features;

Assigning a transparent colour to an image
Create primitive animations
Interlacing
Dithering to simulate colours
Support for custom indexed colour palettes

The following examples are paletted (8-bit), anti-aliased GIF images stored with varying optimized colour palettes:

	Size: 9,705 B Colour Depth: 256 colours An excellent reproduction but the large colour palette is inefficient , producing an unnecessarily large file size.
	Size: 7,993 B Colour Depth: 128 colours A little better in terms of file size, but still inefficient for the same reasons as the 256 colour version.
	Size: 6,654 B Colour Depth: 64 colours Excellent quality equal to the 256 version yet over 3,000 B smaller. This is primarily due to using only a palette 64 colours. This is my choice for best overall image.
	Size: 5,396 B Colour Depth: 32 colours The effects of a smaller colour palette are starting to show in the boat’s hull – notice that it’s a different shade of red now.
	Size: 4,062 B Colour Depth: 16 colours This one deserves an honorable mention. Still a decent repro- duction of the original but only using 16 colours and look at the file size.
	Size: 3,001 B Colour Depth: 8 colours The image is really starting to suffer eight colours with anti-aliasing just doesn’t cut it.
	Size: 2,284 B Colour Depth: 4 colours Look ma, only four colours! In this case ma is disappointed.

Line Art and the GIF format – made for each other