(first instal imagemagick into the server, then it will set the path as follows)
$imagemagicpath=’usr/bin’ //usualy this is the path for image magick
$source=’images/first.jpg’;
//first.jpg is renamed to converted.jpg
//Specifying destination path
$destination=’images/converted.jpg’;
//path for imagemagic function
//specify quality here
$cmd=$imagemagicpath.”/convert “.$source.” -quality 10% “.$destination;
//above line is executing here
exec($cmd);
this will reduce the image quality to 10%
for example first.jpg is initially 120kb it will reduced to 12 kb.