[etc]

Собственно,

MovieClip.prototype.changeScaleAndCoord = function() 
{
		    var dx = this._x - _root._xmouse;
            var dy = this._y - _root._ymouse;
            var dist = Math.sqrt(dx * dx + dy * dy);
			
            if (dist < minDist) this.newScale = minDist - dist; else this.newScale = scale0;
			//изменение масштаба
            this._xscale = this._yscale = this._yscale + (this.newScale - this._yscale) / 10;
		   
			//изменение координат
			if (this.newScale != scale0) _root.moveImg(this.col, this.row, this.newScale * 30);
			this._x += (this.x0 + this.vx - this._x) / 10;
            this._y += (this.y0 + this.vy - this._y) / 10;
			this.vx = this.vx * 0.5;
            this.vy = this.vy * 0.5;
}

vx и vy в начале имеют значения 0.