Most GIF files you see on the web today are made up of an 8-bit palette. Means that there are 256 available colors in any given picture or graphic. But, in most cases the palette can be reduced, which reduces the file size of the GIF, yet still retain acceptable image quality. And, the GIF format allows for the definition of an alternative color palette. This chart shows the bit-depth vs number of colors.
Photos are our first area of study.
This sample image was chosen as representative of many of the considerations found in most photos or renders. Skys are especially difficult to optimize because of the graduation of the dark part of the sky to the light part of the sky and the graduation of solid to transparent cloud activity. Depending on your bandwidth, you may experience a slight delay as these images load. You can also look at our notion of balance between quality and bytesize. While there is some flattening of the colors, it retains sufficient quality to convey the image accurately and pleasantly.