What is the best and fastest way to check if the image is valid in PHP?

Question

What is the best and fastest way to check if the image is valid in PHP ? I need it to be able to check GIF, JPG as well as PNG images.

Answer 1

As recommended by the PHP documentation:

"Do not use getimagesize() to check that a given file is a valid image.Use a purpose-built solution such as the Fileinfo extension instead."

Here is an example:

$finfo = finfo_open(FILEINFO_MIME_TYPE);
$type = finfo_file($finfo, "test.jpg");

if (isset($type) && in_array($type, array("image/png", "image/jpeg", "image/gif"))) {
    echo 'This is an image file';
} else {
    echo 'Not an image :(';
}