src/org/tiefaces/components/websheet/dataobjects/CellMap.java
private String loadPicture(final int rowIndex, final int colIndex) {

		FacesCell facesCell = parent.getCellHelper()
				.getFacesCellWithRowColFromCurrentPage(rowIndex, colIndex);
		if (facesCell != null && facesCell.isContainPic()) {
			FacesContext context = FacesContext.getCurrentInstance();
			String pictureId = facesCell.getPictureId();
			String pictureViewId = Integer.toHexString(
					System.identityHashCode(parent.getWb())) + pictureId;
			Map<String, Object> sessionMap = context.getExternalContext()
					.getSessionMap();
			if (sessionMap.get(pictureViewId) == null) {
				sessionMap.put(pictureViewId, parent.getPicturesMap()
						.get(pictureId).getPictureData());
			}
			return pictureViewId;
		} else {
			return null;
		}
	}
private String loadPicture(final int rowIndex, final int colIndex) {

		FacesCell facesCell = parent.getCellHelper()
				.getFacesCellWithRowColFromCurrentPage(rowIndex, colIndex);
		if (facesCell != null && facesCell.isContainPic()) {
			FacesContext context = FacesContext.getCurrentInstance();
			String pictureId = facesCell.getPictureId();
			String pictureViewId = Integer.toHexString(
					System.identityHashCode(parent.getWb())) + pictureId;
			Map<String, Object> sessionMap = context.getExternalContext()
					.getSessionMap();
			if (sessionMap.get(pictureViewId) == null) {
				sessionMap.put(pictureViewId, parent.getPicturesMap()
						.get(pictureId).getPictureData());
			}
			return pictureViewId;
		} else {
			return null;
		}
	}
Put picture image to session map and return the key to web.

@param rowIndex
the row index of the cell which contains picture.
@param colIndex
the column index of the cell which contains picture.
@return the key of the picture image in the session map.