image gap problem
*The reason for the gap under the picture: The height of the parent element is not set, and it is supported by the picture, so there is a gap*
*method:*
*1. Set the height for the parent element of img, which is consistent with the height of the image;*
*2. Set font-size: 0 for the parent element of img; or line-height: 0; *
*3. Convert the img tag to a block-level tag display: block;*
*4. Set the vertical alignment for the img tag img{vertical-align: not the default value baseline}*