code: function() {
          var style = this.getTile().style,
              size = this.frame ? this.size :
                  this.layer.getImageSize(this.bounds),
              ratio = 1;
          if (this.layer instanceof OpenLayers.Layer.Grid) {
              ratio = this.layer.getServerResolution() / this.layer.map.getResolution();
          }
          style.left = this.position.x + "px";
          style.top = this.position.y + "px";
          style.width = Math.round(ratio * size.w) + "px";
          style.height = Math.round(ratio * size.h) + "px";
      }
docs: Method: positionTile
  Using the properties currenty set on the layer, position the tile correctly.
  This method is used both by the async and non-async versions of the Tile.Image
  code.