"D:\phpStudy\WWW\tubiao\libchart\libchart\classes\view\chart/../../../images/PoweredBy.png"
D:\phpStudy\WWW\tubiao\libchart\libchart\classes\view\chart/../../../
表示当前chart目录向上追溯3层，进入
D:\phpStudy\WWW\tubiao\libchart\libchart目录
再由以上目录进入
images/PoweredBy.png
