Use 'green' electricity
Greenhouse gas emissions
To keep the website running, use electricity that either comes from renewable energy sources, or which has been certified ‘neutral’ by EECS certificates (European Energy Certificate System).
Generate CSS sprite sheets
Group small images (e.g. the website’s interface images) in one larger image called a sprite sheet
This process significantly reduces the number of HTTP requests. There are several free online services for generating sprite sheets (Project Fondue’s CSS Sprite Generator, CSSsprites.com and SpriteMe.org).