JavaScript - NIEVE ACUMULÁNDOSE SOBRE UNA IMAGEN

He encontrado este script y creo que quien sepa de programación en Java podría adaptarlo.
1) Habría que suprimir el comando que elimina los copos detenidos después de cierto tiempo.
2) Habría que reemplazar el ámbito de la página por un rectángulo que contuviera la imagen que queremos "nevar".
3) habría que reemplazar el piso por un elemento que tuviese la forma exterior de los elementos de la imagen que formarián el "nuevo piso", por ejemplo recortar con el Photoshop (eliminar el fondo) y crear con el contorno de esta nueva imagen un nuevo "freno" tal como si se tratase del fondo de la página.
4) Sería conveniente suprimir también los comandos que hacen que la nevada "siga" al mouse.

Alguien podría hacerlo?

<!-- Comienzo del script para nieve -->
<script type="text/javascript">
//<![CDATA[

/*
DHTML Snowstorm! OO-style Jascript-based Snow effect
----------------------------------------------------
Version 1.4.20091115 (Previous rev: v1.3.20081215)
Code by Scott Schiller - http://schillmania.com
----------------------------------------------------

Initializes after body onload() by default (via addEventHandler() call at bottom.)
To customize properties, edit below or override configuration after this script
has run (but before body.onload), eg. snowStorm.snowStick = false;

*/

var snowStorm = null;

function SnowStorm() {

// --- PROPERTIES ---

this.flakesMax = 150; // Limit total amount of snow made (falling + sticking)
this.flakesMaxActive = 64; // Limit amount of snow falling at once (less = lower CPU use)
this.animationInterval = 33; // Theoretical "miliseconds per frame" measurement. 20 = fast + smooth, but high CPU use. 50 = more conservative, but slower
this.flakeBottom = null; // Integer for Y axis snow limit, 0 or null for "full-screen" snow effect
this.targetElement = null; // element which snow will be appended to (document body if null/undefined) - can be an element ID string, or a DOM node reference
this.followMouse = true; // Snow will change movement with the user's mouse
this.snowColor = '#fff'; // Don't eat (or use?) yellow snow.
this.snowCharacter = '•'; // • = bullet, · is square on some systems etc.
this.snowStick = true; // Whether or not snow should "stick" at the bottom. When off, will never collect.
this.useMeltEffect = true; // When recycling fallen snow (or rarely, when falling), have it "melt" and fade out if browser supports it
this.useTwinkleEffect = false; // Allow snow to randomly "flicker" in and out of view while falling
this.usePositionFixed = false; // true = snow not affected by window scroll. may increase CPU load, disabled by default - if enabled, used only where supported

// --- less-used bits ---

this.flakeLeftOffset = 0; // amount to subtract from edges of container
this.flakeRightOffset = 0; // amount to subtract from edges of container
this.flakeWidth = 8; // max pixel width for snow element
this.flakeHeight = 8; // max pixel height for snow element
this.vMaxX = 5; // Maximum X velocity range for snow
this.vMaxY = 4; // Maximum Y velocity range
this.zIndex = 0; // CSS stacking order applied to each snowflake

// --- End of user section ---

// jslint global declarations
/*global window, document, navigator, clearInterval, setInterval */

var addEvent = (typeof(window.attachEvent)=='undefined'?function(o,evtName,evtHandler) {
return o.addEventListener(evtName,evtHandler,false);
}:function(o,evtName,evtHandler) {
return o.attachEvent('on'+evtName,evtHandler);
});

var removeEvent = (typeof(window.attachEvent)=='undefined'?function(o,evtName,evtHandler) {
return o.removeEventListener(evtName,evtHandler,false);
}:function(o,evtName,evtHandler) {
return o.detachEvent('on'+evtName,evtHandler);
});

function rnd(n,min) {
if (isNaN(min)) {
min = 0;
}
return (Math.random()*n)+min;
}

function plusMinus(n) {
return (parseInt(rnd(2),10)==1?n*-1:n);
}

var s = this;
var storm = this;
this.timers = [];
this.flakes = [];
this.disabled = false;
this.active = false;

var isIE = navigator.userAgent.match(/msie/i);
var isIE6 = navigator.userAgent.match(/msie 6/i);
var isOldIE = (isIE && (isIE6 || navigator.userAgent.match(/msie 5/i)));
var isWin9X = navigator.appVersion.match(/windows 98/i);
var isiPhone = navigator.userAgent.match(/iphone/i);
var isBackCompatIE = (isIE && document.compatMode == 'BackCompat');
var noFixed = ((isBackCompatIE || isIE6 || isiPhone)?true:false);
var screenX = null;
var screenX2 = null;
var screenY = null;
var scrollY = null;
var vRndX = null;
var vRndY = null;
var windOffset = 1;
var windMultiplier = 2;
var flakeTypes = 6;
var fixedForEverything = false;
var opacitySupported = (function(){
try {
document.createElement('div').style.opacity = '0.5';
} catch (e) {
return false;
}
return true;
})();
var docFrag = document.createDocumentFragment();
if (s.flakeLeftOffset === null) {
s.flakeLeftOffset = 0;
}
if (s.flakeRightOffset === null) {
s.flakeRightOffset = 0;
}

this.meltFrameCount = 20;
this.meltFrames = [];
for (var i=0; i<this.meltFrameCount; i++) {
this.meltFrames.push(1-(i/this.meltFrameCount));
}

this.randomizeWind = function() {
vRndX = plusMinus(rnd(s.vMaxX,0.2));
vRndY = rnd(s.vMaxY,0.2);
if (this.flakes) {
for (var i=0; i<this.flakes.length; i++) {
if (this.flakes[i].active) {
this.flakes[i].setVelocities();
}
}
}
};

this.scrollHandler = function() {
// "attach" snowflakes to bottom of window if no absolute bottom value was given
scrollY = (s.flakeBottom?0:parseInt(window.scrollY||document.documentElement.scrollTop||document.body.scrollTop,10));
if (isNaN(scrollY)) {
scrollY = 0; // Netscape 6 scroll fix
}
if (!fixedForEverything && !s.flakeBottom && s.flakes) {
for (var i=s.flakes.length; i-- {
if (s.flakes[i].active === 0) {
s.flakes[i].stick();
}
}
}
};

this.resizeHandler = function() {
if (window.innerWidth || window.innerHeight) {
screenX = window.innerWidth-(!isIE?16:2)-s.flakeRightOffset;
screenY = (s.flakeBottom?s.flakeBottom:window.innerHeight);
} else {
screenX = (document.documentElement.clientWidth||document.body.clientWidth||document.body.scrollWidth)-(!isIE?8:0)-s.flakeRightOffset;
screenY = s.flakeBottom?s.flakeBottom:(document.documentElement.clientHeight||document.body.clientHeight||document.body.scrollHeight);
}
screenX2 = parseInt(screenX/2,10);
};

this.resizeHandlerAlt = function() {
screenX = s.targetElement.offsetLeft+s.targetElement.offsetWidth-s.flakeRightOffset;
screenY = s.flakeBottom?s.flakeBottom:s.targetElement.offsetTop+s.targetElement.offsetHeight;
screenX2 = parseInt(screenX/2,10);
};

this.freeze = function() {
// pause animation
if (!s.disabled) {
s.disabled = 1;
} else {
return false;
}
for (var i=s.timers.length; i-- {
clearInterval(s.timers[i]);
}
};

this.resume = function() {
if (s.disabled) {
s.disabled = 0;
} else {
return false;
}
s.timerInit();
};

this.toggleSnow = function() {
if (!s.flakes.length) {
// first run
s.start();
} else {
s.active = !s.active;
if (s.active) {
s.show();
s.resume();
} else {
s.stop();
s.freeze();
}
}
};

this.stop = function() {
this.freeze();
for (var i=this.flakes.length; i-- {
this.flakes[i].o.style.display = 'none';
}
removeEvent(window,'scroll',s.scrollHandler);
removeEvent(window,'resize',s.resizeHandler);
if (!isOldIE) {
removeEvent(window,'blur',s.freeze);
removeEvent(window,'focus',s.resume);
}
};

this.show = function() {
for (var i=this.flakes.length; i-- {
this.flakes[i].o.style.display = 'block';
}
};

this.SnowFlake = function(parent,type,x,y) {
var s = this;
var storm = parent;
this.type = type;
this.x = x||parseInt(rnd(screenX-20),10);
this.y = (!isNaN(y)?y:-rnd(screenY)-12);
this.vX = null;
this.vY = null;
this.vAmpTypes = [1,1.2,1.4,1.6,1.8]; // "amplification" for vX/vY (based on flake size/type)
this.vAmp = this.vAmpTypes[this.type];
this.melting = false;
this.meltFrameCount = storm.meltFrameCount;
this.meltFrames = storm.meltFrames;
this.meltFrame = 0;
this.twinkleFrame = 0;
this.active = 1;
this.fontSize = (10+(this.type/5)*10);
this.o = document.createElement('div');
this.o.innerHTML = storm.snowCharacter;
this.o.style.color = storm.snowColor;
this.o.style.position = (fixedForEverything?'fixed':'absolute');
this.o.style.width = storm.flakeWidth+'px';
this.o.style.height = storm.flakeHeight+'px';
this.o.style.fontFamily = 'arial,verdana';
this.o.style.overflow = 'hidden';
this.o.style.fontWeight = 'normal';
this.o.style.zIndex = storm.zIndex;
docFrag.appendChild(this.o);

this.refresh = function() {
if (isNaN(s.x) || isNaN(s.y)) {
// safety check
return false;
}
s.o.style.left = s.x+'px';
s.o.style.top = s.y+'px';
};