uploadPhoto method not working

I am using uploadPhoto method to attach photos to my Leads. I am using PHP for the same. However, when I tried to execute the URL mentioned in the API using curl, it displays an error message saying "Unable to process your request. Please verify whether you have provided proper file." I double checked the type and path of the file I am trying to post, but it doesn't seem to work.

Here is the PHP for reference:

$recordId="873040000000074005";

$path = "http://www.codeblocs.com/99/upload/images.png";

$ch=curl_init();

curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);

curl_setopt($ch,CURLOPT_URL,"https://crm.zoho.com/crm/private/xml/Leads/uploadPhoto?authtoken=6169e6024147f05cfd8fb1f00ba58d3c&scope=crmapi");

curl_setopt($ch,CURLOPT_POST,true);

$post=array("id"=>$recordId,"content"=>$path);

curl_setopt($ch,CURLOPT_POSTFIELDS,$post);

$response=curl_exec($ch);

echo $response;

Any help or assistance is appreciated.

Thanks