function calculateWidth(image)
        {
            var naturalHeight = image.naturalHeight;
            if (!naturalHeight)
                return;
            var naturalWidth = image.naturalWidth;
            this._imageHeight = this._canvas.height - 10
            this._imageWidth = Math.floor(this._imageHeight * naturalWidth / naturalHeight);
        }
@this {WebInspector.TimelineFilmStripOverview}
@param {!HTMLImageElement} image