It's probably a problem on both, but they have different error display settings, so you aren't seeing the error message displayed on the web page on one of them.
I don't know what context you are using the getimagesize() in, but you'll need to access the additional array index that will be added due to the use of the "[]" on the name:
$size=getimagesize($_FILES['images']['tmp_name'][0]);
That last index will be 0 for the first image, 1, for the second, etc. just like any other default array indexing scheme. Depending on exactly what you are doing, you might want to do a foreach loop:
foreach($_FILES['images']['tmp_name'] as $thisImage)
{
if(!empty($thisImage))
{
$size=getimagesize($thisImage);
// do whatever you want to do with $size
}
}
