i've seen some downvotes , here is a small example of using curl to upload image .
<?php
$target="http://youraddress.tld/example/upload.php";
# http://php.net/manual/en/curlfile.construct.php
// Create a CURLFile object / procedural method
$cfile = curl_file_create('resource/test.png','image/png','testpic'); // try adding
// Create a CURLFile object / oop method
#$cfile = new CURLFile('resource/test.png','image/png','testpic'); // uncomment and use if the upper procedural method is not working.
// Assign POST data
$imgdata = array('myimage' => $cfile);
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $target);
curl_setopt($curl, CURLOPT_USERAGENT,'Opera/9.80 (Windows NT 6.2; Win64; x64) Presto/2.12.388 Version/12.15');
curl_setopt($curl, CURLOPT_HTTPHEADER,array('User-Agent: Opera/9.80 (Windows NT 6.2; Win64; x64) Presto/2.12.388 Version/12.15','Referer: http://someaddress.tld','Content-Type: multipart/form-data'));
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false); // stop verifying certificate
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true); // enable posting
curl_setopt($curl, CURLOPT_POSTFIELDS, $imgdata); // post images
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); // if any redirection after upload
$r = curl_exec($curl);
curl_close($curl);
?>