Google Chart API

“The Google Chart API returns a PNG -format image in response to a URL . Several types of image can be generated: line, bar, and pie charts for example. For each image type you can specify attributes such as size, colors, and labels.” 
 “You can include a Chart API image in a webpage by embedding a URL within an tag. When the webpage is displayed in a browser the Chart API renders the image within the page.” 
 “This document describes the required format of Chart API URLs and the available parameters.” 
 See: http://code.google.com/apis/chart/