Exif Functions
is this function usefull for finding if a file is an image?
exif_imagetype
(PHP 4 >= 4.3.0, PHP 5)
exif_imagetype — Determine the type of an image
Description
int exif_imagetype
( string $filename
)
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.
Parameters
- filename
- The image being checked.
Return Values
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.
ChangeLog
| Version | Description |
|---|---|
| 4.3.2 | Support for JPC, JP2, JPX, JB2, XBM, and WBMP |
| 4.3.0 | Support for SWC |
Predefined Constants
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 |
Examples
Example #1 exif_imagetype() example
<?php
if (exif_imagetype('image.gif') != IMAGETYPE_GIF) {
echo 'The picture is not a gif';
}
?>
add a note
User Contributed Notesexif_imagetype
alastors at gmail dot com
04-Jul-2008 02:39
04-Jul-2008 02:39
tom dot ghyselinck at telenet dot be
13-Jan-2008 05:36
13-Jan-2008 05:36
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 $type;
}
return false;
}
}
Tim
20-Nov-2007 12:40
20-Nov-2007 12:40
By trial and error, it seems that a file has to be 12 bytes or larger in order to avoid a "Read error!". Here's a work-around to avoid an error being thrown:
// exif_imagetype throws "Read error!" if file is too small
if (filesize($uploadfile) > 11)
$mimetype = exif_imagetype($uploadfile);
else
$mimetype = false;
10-Nov-2006 08:43
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
08-Feb-2004 06:11
08-Feb-2004 06:11
libexif can also be used to parse image info out of id3 tags:
exif_read_data("mp3_with_2.4ID3TAGS, '', true, false);
tilmauder at yahoo dot com
06-Jul-2003 07:57
06-Jul-2003 07:57
After looking for hours, I found a very good source for exif related programs here: http://drewnoakes.com/code/exif/index.html
It lists exif specifications (pdf), a few good links to exif related stuff. The best source I have found in my quest to understand exif better for use in php based exif tools.