Sending imagepng() object to server using cURL - php

Question

I'm trying to take an imagepng() object and upload it to a different server using cURL. Here is the code I've got. To be clear, I know the imagepng file works correctly and is being generated because I can save it locally on the server the code is running on. I'm just not sure how to send that info to a new server. All of the variables are set before this code ($fileName, $imageObject, etc.):
$file = imagepng($imageObject, 'newTest'.$counter.'.png');
if($file){
$ch = curl_init();
$fp = $file;
curl_setopt($ch, CURLOPT_URL, 'ftp://'.$ftp_user.':'.$ftp_pass.'#'.$ftp_server.'/'.$fileName.'.png');
curl_setopt($ch, CURLOPT_UPLOAD, 1);
curl_setopt($ch, CURLOPT_INFILE, $fp);
curl_setopt($ch, CURLOPT_INFILESIZE, filesize($file));
curl_exec ($ch);
$error_no = curl_errno($ch);
curl_close ($ch);
if ($error_no == 0) {
$error = 'File uploaded succesfully.';
} else {
$error = 'File upload error.';
}
}
The errors I am getting for every file (this code is in a loop processing multiple files) is. Of course {MY_URL} is replaced with the actual URL of my file:
Warning: curl_setopt(): supplied argument is not a valid File-Handle resource in {MY_URL} on line 43
Warning: filesize() [function.filesize]: stat failed for 1 in {MY_URL} on line 44
So it appears that the file is the wrong format when it's being cURLed. What do I need to set it to in order to send it correctly?
Thanks for your help!

Answer 1

imagepng outputs image into a file,but does not return a file handle (it only returns TRUE in case of success). You need to use something like fopen to get a valid file handle. Try replacing $fp=$file with this:
$fp = fopen('newTest'.$counter.'.png', "rb");
Also, replace filesize($file) with filesize($fp).
In general, $file is just a boolean, not a file handle. Use $fp for every function that expects a file handle. Also, don't forget to close every file at the end of the loop (e.g. add the following line after curl_close):
fclose($fp);