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 a better solution.

This method is faster than using getimagesize. To quote php.net "The return value is the same value that getimagesize() returns in index 2 but exif_imagetype() is much faster."

if(exif_imagetype('path/to/image.jpg')) {
    // your image is valid
}

Update:

After reading that getimagesize can be unreliable I tried to find some more info on what file types can give false positives but could not find any more info so performed a brief test (using exif_imagetype):

PowerPoint-survey-results.pptx - N
LRMonoPhase4.wav               - N
TestWordDoc.doc                - N
drop.avi                       - N
test.dll                       - N
raw_data_sample.sav            - N
text.txt                       - N
Excel-survey-results.xlsx      - N
pdf-test.pdf                   - N
simplepie-1.5.zip              - N
Word-survey-results.docx       - N
centaur_1.mpg                  - N
Test.svg                       - N
multipage_tif_example.tif      - Y
200.gif                        - Y
Test.png                       - Y
test.jpg                       - Y

I realise this is not exhaustive however at least show that with common file types the results are as expected.

Answer 2

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 :(';
}

Answer 3

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;
}

Answer 4

I use this function... it checks urls too

function isImage($url){
   $params = array('http' => array(
                'method' => 'HEAD'
             ));
   $ctx = stream_context_create($params);
   $fp = @fopen($url, 'rb', false, $ctx);
   if (!$fp) 
      return false;  // Problem with url

  $meta = stream_get_meta_data($fp);
  if ($meta === false){
      fclose($fp);
      return false;  // Problem reading data from url
  }
 }

Answer 5

I guess getimagesize:

list($width, $height, $type, $attr) = getimagesize("path/to/image.jpg");

if (isset($type) && in_array($type, array(
    IMAGETYPE_PNG, IMAGETYPE_JPEG, IMAGETYPE_GIF))) {
  ...
}

Answer 6

I use this:

function is_image($path)
{
    $a = getimagesize($path);
    $image_type = $a[2];

    if(in_array($image_type , array(IMAGETYPE_GIF , IMAGETYPE_JPEG ,IMAGETYPE_PNG , IMAGETYPE_BMP)))
    {
        return true;
    }
    return false;
}