php如何获取以kb为单位的网络图像大小？
getimagesize只得到宽度和高度。
并filesize造成waring.
$imgsize=filesize("http://static.adzerk.net/Advertisers/2564.jpg");
echo $imgsize;
Warning: filesize() [function.filesize]: stat failed for http://static.adzerk.net/Advertisers/2564.jpg
有没有其他方法可以获取以 kb 为单位的网络图像大小？
没有做一个完整的 HTTP 请求，没有简单的方法：
$img = get_headers("http://static.adzerk.net/Advertisers/2564.jpg", 1);
print $img["Content-Length"];
但是，您可以使用cURL发送更轻松的HEAD请求来代替。
<?php
$file_size = filesize($_SERVER['DOCUMENT_ROOT']."/Advertisers/2564.jpg"); // Get file size in bytes
$file_size = $file_size / 1024; // Get file size in KB
echo $file_size; // Echo file size
?>
不确定是否使用filesize()远程文件，但 php.net 上有很好的片段，尽管关于使用 cURL。
这听起来像是一个权限问题，因为 filesize() 应该可以正常工作。
这是一个例子：
php > echo filesize("./9832712.jpg");
1433719
确保在图像上正确设置了权限，并且路径也正确。您将需要应用一些数学来从字节转换为 KB，但这样做之后您应该处于良好状态！
您也可以使用此功能
<?php
$filesize=file_get_size($dir.'/'.$ff);
$filesize=$filesize/1024;// to convert in KB
echo $filesize;
function file_get_size($file) {
//open file
$fh = fopen($file, "r");
//declare some variables
$size = "0";
$char = "";
//set file pointer to 0; I'm a little bit paranoid, you can remove this
fseek($fh, 0, SEEK_SET);
//set multiplicator to zero
$count = 0;
while (true) {
//jump 1 MB forward in file
fseek($fh, 1048576, SEEK_CUR);
//check if we actually left the file
if (($char = fgetc($fh)) !== false) {
//if not, go on
$count ++;
} else {
//else jump back where we were before leaving and exit loop
fseek($fh, -1048576, SEEK_CUR);
break;
}
}
//we could make $count jumps, so the file is at least $count * 1.000001 MB large
//1048577 because we jump 1 MB and fgetc goes 1 B forward too
$size = bcmul("1048577", $count);
//now count the last few bytes; they're always less than 1048576 so it's quite fast
$fine = 0;
while(false !== ($char = fgetc($fh))) {
$fine ++;
}
//and add them
$size = bcadd($size, $fine);
fclose($fh);
return $size;
}
?>
您可以使用 get_headers() 函数获取文件大小。使用以下代码：
$image = get_headers($url, 1);
$bytes = $image["Content-Length"];
$mb = $bytes/(1024 * 1024);
echo number_format($mb,2) . " MB";