/* creates a compressed zip file */ 
function create_zip($files = array(),$destination = '',$overwrite = false) { 
//if the zip file already exists and overwrite is false, return false 
if(file_exists($destination) && !$overwrite) { return false; } 
//vars 
$valid_files = array(); 
//if files were passed in... 
if(is_array($files)) { 
//cycle through each file 
foreach($files as $file) { 
//make sure the file exists 
if(file_exists($file)) { 
$valid_files[] = $file; 
} 
} 
} 
//if we have good files... 
if(count($valid_files)) { 
//create the archive 
$zip = new ZipArchive(); 
if($zip->open($destination,$overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true) { 
return false; 
} 
//add the files 
foreach($valid_files as $file) { 
$zip->addFile($file,$file); 
} 
//debug 
//echo 'The zip archive contains ',$zip->numFiles,' files with a status of ',$zip->status; 

//close the zip -- done! 
$zip->close(); 

//check to make sure the file exists 
return file_exists($destination); 
} 
else 
{ 
return false; 
} 
} 
/***** Example Usage ***/ 
$files=array('file1.jpg', 'file2.jpg', 'file3.gif'); 
create_zip($files, 'myzipfile.zip', true);