如果我使用背景图像会有性能问题吗

I came to know that, if we dont give width and height attr. in image tag there will be a performance isssue. I have a div element for which i'm setting width and height in percentages. Also the same div is having a background image of fixed size say 140px * 140px. Here, will there be a perfromance issuse?.I came to know that, if we dont give width and