javascript悬停图片并显示左上角到右下角

I have a picture with 40Px 40Px when the cursor hovers over the image, then the image should be 100px 100px with, but to open slow left top to bottom right or right top to bottom left.When I move the cursor to the image back to its original position accurately 40px 40px. Thanks in advanceI have a picture with 40Px 40Px when the cursor