图像使用JQUERY自动调整大小/缩放

I have a div with width 600 px. I want to pull the images dynamically. Images size are varies. What I want to do is, if the image size is more than 600 px, we will resize the image to 600 px to fit into the div. But if the image is not more than 600px, we will leave as original image width. I have a div with width 600 px. I want to pull