Web Gradients is a tool for creating simple and smooth PNG linear gradients with plain HTTP requests (or this page).
Just a GET to /make?width=(pixels)&height=(pixels)&start=(hex)&end=(hex)&direction=(up|down|left|right). All parameters are optional. Default width is 1 pixel, height - 100. Default start color is eeeeec, end is d3d7cf, direction is down.