PHP check IF non-empty, non-zero - php

Question

I get the width and height of image with getimagesize function, like below:
list($width,$height) = getimagesize($source_pic);
How can I use IF condition to check that the getimagesize function executed without error and $width and $height got non-empty, non-zero values?

Answer 1

if ($size = getimagesize($source_pic)) {
list($width,$height) = $size;
if($height > 0 && $width > 0) {
// do stuff
}
}

Answer 2

if ($width === NULL) {
//handle error
}
If there's an error getimagesize returns FALSE, not an an array, so the list assignment will result in the variables being NULL.

Answer 3

This should be enough:
list($width, $height) = getimagesize($source_pic);
if( $width>0 && $height>0 ){
// Valid image with known size
}
If it isn't a valid image, both $width and $height will be NULL. If it's a valid image but PHP could not determine its dimensions, they'll be 0.
A note from the manual:
Some formats may contain no image or
may contain multiple images. In these
cases, getimagesize() might not be
able to properly determine the image
size. getimagesize() will return zero
for width and height in these cases.

Answer 4

$size = getimagesize('image.jpg');
list($height,$width) = getimagesize('image.jpg');
if($height>0 && $width>0){
//it comes into if block if and only if both are not null
}