Dithering

Dithering can decrease a file size by a great deal. This photo with three-color dithering is 7.3KB, 68x smaller than the webp-compressed version which is 500KB.

The eastbound Kate Shelley 400 arriving at DeKalb in December 1964. Photo by Roger Puta.

Passengers waiting for a yellow train in snowy winter.

Passengers waiting for a yellow train in snowy winter, rendered in low resolution with dark, light, and yellow dots.

Dithering reduced this photo of a house from 1.7MB to 16KB. Even with 4 colors, it’s 106x smaller.

A vine covered house. Photo by me.

The side of a vine-covered house with a spiral staircase, obscured by vegetation.

The side of a vine-covered house with a spiral staircase, obscured by vegetation, rendered in low resolution with dark, light, orange, and green dots.