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

exif_imagetype is much faster than getimagesize and doesn't use gd-Lib (leaving a leaner mem footprint)

function isImage($pathToFile)
{
  if( false === exif_imagetype($pathToFile) )
   return FALSE;

   return TRUE;
}