If you want it to be a percent of the current width and height:Ex. 9% current width and height
CODE
list($width,$height,$type,$attr) = getimagesize("http://www.nexusatlas.com/image.jpg");
$newWidth = $width*0.09;
$newHeight = $height*0.09;
Ex. 219% curent width and height
CODE
list($width,$height,$type,$attr) = getimagesize("http://www.nexusatlas.com/image.jpg");
$newWidth = $width*2.19;
$newHeight = $height*2.19;
If you want the new height and width to be based off of a standard height or width:Ex. all images to have standard 200 width
CODE
list($width,$height,$type,$attr) = getimagesize("http://www.nexusatlas.com/image.jpg");
//height/width = x/200
$newWidth = 200;
$newHeight = ($height*200)/$width;
Ex. all images to have standard 50 height
CODE
list($width,$height,$type,$attr) = getimagesize("http://www.nexusatlas.com/image.jpg");
//height/width = 50/x
$newHeight = 50;
$newWidth = ($width*50)/$height;