public String getImg()throws Exception{
        HttpServletResponse response=null; 
        ServletOutputStream out = null; 
        response=ServletActionContext.getResponse(); 
        response.setContentType( "multipart/form-data" );           
        out = response.getOutputStream();
                   //从数据库得到图片存放路径，获取图片转换成流
        byte[] picByte=Base64.decode(daoImpl.getBytesFile(new File(ItemVo.getPicturePath())));
        try{            
            out.write(picByte);
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            if(out!=null){
                out.close();
            }
        }


        return null;
    }

<action name="Image" class="com.sdjg.struts.action.xxx.WapAction" method="getImg"></action>

<img src="<s:url action="Image"><s:param name="pictureIndex" value="id"></s:param></s:url>">