如果您不希望图像拉伸，则应固定一个尺寸，而将另一个尺寸设为auto。（这将保留图像的长宽比）
请参阅下面的示例，其中width在height自动调整时保持不变：
img { display: block;}.correct,.incorrect { border: 1px solid red; display: inline-block;}.incorrect img { max-width: 100%; width: 100px; height: 100px;}.correct img { max-width: 100%; width: 200px; height: auto;}<div>This one stretches out:</div><div > <img src="http://placehold.it/150x50" /></div><div>This will preserve aspect ratio and look right:</div><div > <img src="http://placehold.it/150x50" /></div>请参阅下面的示例，其中height在width自动调整时保持不变：
img { display: block;}.correct,.incorrect { border: 1px solid red; display: inline-block;}.incorrect img { max-height: 100%; height: 100px; width: 100px;}.correct img { max-height: 100%; height: 200px; width: auto;}<div>This one stretches out:</div><div > <img src="http://placehold.it/150x50" /></div><div>This will preserve aspect ratio and look right:</div><div > <img src="http://placehold.it/150x50" /></div>
