<img src="abc.png" alt="abc" width="580" height="267" />

<img src="abc.png" alt="abc" />

add_filter( 'post_thumbnail_html', 'remove_width_attribute', 10 );
add_filter( 'image_send_to_editor', 'remove_width_attribute', 10 );
function remove_width_attribute( $html ) {
$html = preg_replace( '/(width|height)="\d*"\s/', "", $html );
return $html;
}

// 自適應圖片刪除width和height，by Ludou
function ludou_remove_width_height_attribute($content){
preg_match_all("/<[img|IMG].*?src=[\'|\"](.*?(?:[\.gif|\.jpg|\.png\.bmp]))[\'|\"].*?[\/]?>/", $content, $images);
if(!empty($images)) {
foreach($images[0] as $index => $value){
$new_img = preg_replace('/(width|height)="\d*"\s/', "", $images[0][$index]);
$content = str_replace($images[0][$index], $new_img, $content);
}
}
return $content;
}
// 判斷是否是移動設備瀏覽
if(wp_is_mobile()) {
// 刪除文章內容中img的width和height屬性
add_filter('the_content', 'ludou_remove_width_height_attribute', 99);
}