рони,
<img id="image" src="http://javascript.ru/cat/list/project.jpg">
<canvas id="canvas" width="200" height="50"></canvas>
<script>
window.onload = function() {
var canvas = document.getElementById('canvas');
var image = document.getElementById('image');
var context = canvas.getContext('2d');
context.globalAlpha = 0.8;
context.drawImage(image, 0, 0);
context.globalAlpha = 0.6;
context.drawImage(image, 50, 0);
context.globalAlpha = 0.4;
context.drawImage(image, 100, 0);
context.globalAlpha = 0.2;
context.drawImage(image, 150, 0);
context.globalAlpha = 1;
};
</script>