在手机safari上传图片时，竖着的照片会变成横着的照片，以下程序片段利用图片exif信息把图片旋转回去，代码抄自php.net官网。
http://php.net/manual/zh/function.exif-read-data.php
<span style="color: #000000;">php
</span><span style="color: #800080;">$image</span> = imagecreatefromstring(<span style="color: #008080;">file_get_contents</span>(<span style="color: #800080;">$_FILES</span>['image_upload']['tmp_name'<span style="color: #000000;">]));
</span><span style="color: #800080;">$exif</span> = exif_read_data(<span style="color: #800080;">$_FILES</span>['image_upload']['tmp_name'<span style="color: #000000;">]);
</span><span style="color: #0000ff;">if</span>(!<span style="color: #0000ff;">empty</span>(<span style="color: #800080;">$exif</span>['Orientation'<span style="color: #000000;">])) {
</span><span style="color: #0000ff;">switch</span>(<span style="color: #800080;">$exif</span>['Orientation'<span style="color: #000000;">]) {
</span><span style="color: #0000ff;">case</span> 8:
<span style="color: #800080;">$image</span> = imagerotate(<span style="color: #800080;">$image</span>,90,0<span style="color: #000000;">);
</span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
</span><span style="color: #0000ff;">case</span> 3:
<span style="color: #800080;">$image</span> = imagerotate(<span style="color: #800080;">$image</span>,180,0<span style="color: #000000;">);
</span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
</span><span style="color: #0000ff;">case</span> 6:
<span style="color: #800080;">$image</span> = imagerotate(<span style="color: #800080;">$image</span>,-90,0<span style="color: #000000;">);
</span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
}
}
</span><span style="color: #008000;">//以下代码自行处理即可</span>
?>
