当网址包含.jpg和帖子字段时，PHP curl无法正常工作

I am using php curl to ping and post data to a url. But it is not working.response of url is "not found" this comes when the posting url is "http://example.com/conversion_get/" I suspect it was because of .jpg in curl url. I am using same code in same application to post data. but it works fine. Can any body help me to sort out this issue?

My code:

    $kps="6789345607655ABF5k23929ocern46789345607655ABF5k23929ocern4";
    $url="http://example.com/conversion_get/pixel.jpg";
    $ch = curl_init();
    if (!$ch){die("Couldn't initialize a cURL handle");}
    $ret = curl_setopt($ch, CURLOPT_URL,$url);
    curl_setopt ($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
    curl_setopt ($ch, CURLOPT_POSTFIELDS,     "kp=".$kps);
    $ret = curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $curlresponse = curl_exec($ch);
    curl_setopt($ch, CURLOPT_HEADER, 0);

    if(curl_errno($ch))
    echo 'curl error : '. curl_error($ch);
    if (empty($ret)) {
    curl_close($ch);
    } else {
    $info = curl_getinfo($ch);
    curl_close($ch); // close cURL handler
    $ns= $curlresponse; 
       }