最好的解决方案是读取文件,然后确定它是哪种图像并发送适当的标头
$filename = basename($file);
$file_extension = strtolower(substr(strrchr($filename,"."),1));
switch( $file_extension ) {
case "gif": $ctype="image/gif"; break;
case "png": $ctype="image/png"; break;
case "jpeg":
case "jpg": $ctype="image/jpeg"; break;
case "svg": $ctype="image/svg+xml"; break;
default:
}
header('Content-type: ' . $ctype);
(注意:JPG文件的正确内容类型是image/jpeg
)