Get remote image using cURL then resample

问题

I want to be able to retrieve a remote image from a webserver, resample it, and then serve it up to the browser AND save it to a file. Here is what I have so far:

$ch = curl_init();

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "$rURL");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_HEADER, 0);

// grab URL and pass it to the browser
$out = curl_exec($ch);

// close cURL resource, and free up system resources
curl_close($ch);

$imgRes = imagecreatefromstring($out);
imagejpeg($imgRes, $filename, 70);

header("Content-Type: image/jpg");
imagejpeg($imgRes, NULL, 70);
exit();

Update

Updated to reflect correct answer based on discussion below

回答1:

You can fetch the file into a GD resource using imagecreatefromstring():

imagecreatefromstring() returns an image identifier representing the image obtained from the given data. These types will be automatically detected if your build of PHP supports them: JPEG, PNG, GIF, WBMP, and GD2.

from there, it's pretty straightforward using imagecopyresampled().

Output it using imagejpeg() or whichever output format suits you best.

Make one output with a file name:

imagejpeg($image_resource, "/path/to/image.jpg");

then send the same resource to the browser:

header("Content-type: image/jpeg");
imagejpeg($image_resource);

depending on the image's format, you may want to use the imagepng() or imagegif() functions instead.

You may want to work with different output formats depending on the input file type. You can fetch the input file type using getimagesize().

Remember that you can adjust the resulting JPEG image's quality using the $quality parameter. Default is 75% which can look pretty crappy.

来源：https://stackoverflow.com/questions/2629433/get-remote-image-using-curl-then-resample