为什么图片上传失败 php 的 is_uploaded_file 检查?

I have a html form that allows image uploads, but the image uploaded now fails the "is_uploaded_file" check for some reason.

那么为什么上传失败了 is_uploaded_file 检查?

HTML:

<form enctype="multipart/form-data" id="RecipeAddForm" method="post"
action="/recipes/add" accept-charset="utf-8">
    <!--- Omitted Markup -->
    <input type="file" name="data[Recipe][image]" value="" id="RecipeImage" />
    <!--- Omitted Markup -->
</form>

PHP:

// returns false
echo is_uploaded_file($file['tmp_name'])?'true':'false'; 

我对 $file 或 $_FILES 数组进行了转储:

Array
(
    [name] => add or remove.jpg
    [type] => image/jpeg
    [tmp_name] => E:\xampp\tmp\phpB9CB.tmp
    [error] => 0
    [size] => 71869
)