图片自适应手机屏幕宽度CSS

img {    
 border-width: 0px; 
 border-style: none; 
 vertical-align: top; 
 box-sizing: border-box !important; 
 word-wrap: break-word !important; 
 visibility: visible !important; 
 width: 100% !important; 
 height: auto !important;
}