ImageCreateFromString and getimagesize in PHP

Question

Currently if a user POST/uploads a photo to my PHP script I start out with some code like this

getimagesize($_FILES[\'picture1\'][\'tmp_name\']);

Answer 1

I suggest you follow this approach:

// if you need the image type
$type = exif_imagetype($url);

// if you need the image mime type
$type = image_type_to_mime_type(exif_imagetype($url));

// if you need the image extension associated with the mime type
$type = image_type_to_extension(exif_imagetype($url));

// if you don't care about the image type ignore all the above code
$image = ImageCreateFromString(file_get_contents($url));

echo ImageSX($image); // width
echo ImageSY($image); // height

Using exif_imagetype() is a lot faster than getimagesize(), the same goes for ImageSX() / ImageSY(), plus they don't return arrays and can also return the correct image dimension after the image has been resized or cropped for instance.

Also, using getimagesize() on URLs isn't good because it'll consume much more bandwidth than the alternative exif_imagetype(), from the PHP Manual:

When a correct signature is found, the appropriate constant value will be returned otherwise the return value is FALSE. The return value is the same value that getimagesize() returns in index 2 but exif_imagetype() is much faster.

That's because exif_imagetype() will only read the first few bytes of data.