By trial and error, it seems that a file has to be 12 bytes or larger in order to avoid a "Read error!". Here's a work-around to avoid an error being thrown:
// exif_imagetype throws "Read error!" if file is too small
if (filesize($uploadfile) > 11)
$mimetype = exif_imagetype($uploadfile);
else
$mimetype = false;
exif_imagetype
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
exif_imagetype — Determine the type of an image
Descrizione
exif_imagetype() reads the first bytes of an image and checks its signature.
exif_imagetype() can be used to avoid calls to other exif functions with unsupported file types or in conjunction with $_SERVER['HTTP_ACCEPT'] to check whether or not the viewer is able to see a specific image in the browser.
Elenco dei parametri
-
filename - The image being checked.
Valori restituiti
When a correct signature is found, the appropriate constant value will be
returned otherwise the return value is false. The return value is the
same value that getimagesize() returns in index 2 but
exif_imagetype() is much faster.
The following constants are defined, and represent possible exif_imagetype() return values:
| Value | Constant |
|---|---|
| 1 | IMAGETYPE_GIF |
| 2 | IMAGETYPE_JPEG |
| 3 | IMAGETYPE_PNG |
| 4 | IMAGETYPE_SWF |
| 5 | IMAGETYPE_PSD |
| 6 | IMAGETYPE_BMP |
| 7 | IMAGETYPE_TIFF_II (intel byte order) |
| 8 |
IMAGETYPE_TIFF_MM (motorola byte order)
|
| 9 | IMAGETYPE_JPC |
| 10 | IMAGETYPE_JP2 |
| 11 | IMAGETYPE_JPX |
| 12 | IMAGETYPE_JB2 |
| 13 | IMAGETYPE_SWC |
| 14 | IMAGETYPE_IFF |
| 15 | IMAGETYPE_WBMP |
| 16 | IMAGETYPE_XBM |
| 17 | IMAGETYPE_ICO |
| 18 | IMAGETYPE_WEBP |
| 19 | IMAGETYPE_AVIF |
Nota:
exif_imagetype() will emit an
E_NOTICEand returnfalseif it is unable to read enough bytes from the file to determine the image type.
Log delle modifiche
| Versione | Descrizione |
|---|---|
| 7.1.0 | Added WebP support. |
| 8.1.0 | Added AVIF support. |
Esempi
Example #1 exif_imagetype() example
<?php
if (exif_imagetype('image.gif') != IMAGETYPE_GIF) {
echo 'The picture is not a gif';
}
?>Vedere anche:
- image_type_to_mime_type() - Get Mime-Type for image-type returned by getimagesize, exif_read_data, exif_thumbnail, exif_imagetype
- getimagesize() - Get the size of an image
add a note
User Contributed Notes 7 notes
Tim ¶
16 years ago
christophe dot tournayre at univ*bpclermont dot Fr ¶
11 years ago
Because I only want to check for jpeg or png from a memory string, this is my 2 functions that are quick and don't have any dependencies :
<?php
function is_jpeg(&$pict)
{
return (bin2hex($pict[0]) == 'ff' && bin2hex($pict[1]) == 'd8');
}
function is_png(&$pict)
{
return (bin2hex($pict[0]) == '89' && $pict[1] == 'P' && $pict[2] == 'N' && $pict[3] == 'G');
}
?>
admin at leonard !spam challis dot com ¶
14 years ago
Windows users: If you get the fatal error "Fatal error: Call to undefined function exif_imagetype()", and you have enabled php_exif.dll, make sure you enable php_mbstring.dll. You must put mbstring before exif in the php.ini, i.e.:
extension=php_mbstring.dll
extension=php_exif.dll
You can check whether this has worked by calling phpinfo() and searching for exif.
tom dot ghyselinck at telenet dot be ¶
16 years ago
If the function exif_imagetype() is not available,
you can try the following workaround:
if ( ! function_exists( 'exif_imagetype' ) ) {
function exif_imagetype ( $filename ) {
if ( ( list($width, $height, $type, $attr) = getimagesize( $filename ) ) !== false ) {
return $type;
}
return false;
}
}
vuatintac at yahoo dot com ¶
9 years ago
to checking file is image, I used this:
function is_image($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;
}
Anonymous ¶
18 years ago
Seems to give a 'Read error' warning if the size of the file is very small (2 bytes). I think this is because it needs a min 3 bytes to determine the file type
tom at tomvergote dot be ¶
20 years ago
libexif can also be used to parse image info out of id3 tags:
exif_read_data("mp3_with_2.4ID3TAGS, '', true, false);
