Several simple picture judgment functions in php_PHP tutorial

int exif_imagetype ( string $filename )
1 imagetype_gif
2 imagetype_jpeg
3 imagetype_png
4 imagetype_swf
5 imagetype_ps tutorial d
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

*/
$img="image.gif"; //Definition file
if(exif_imagetype($img)!=imagetype_gif) //Determine the file type
{
echo "The specified image is not a gif image"; //Output result
}
else
{
echo "The specified picture is a gif picture";
}

/*
array exif_read_data ( string $filename [, string $sections = null [, bool $arrays = false [, bool $thumbnail = false ]]] )

*/

echo "test1.jpg:
n"; //Output file name
$exif=exif_read_data('tests/test1.jpg','ifd0'); //Read file 1 information
                    //Judge based on the results
echo $exif===false ? "no header data found.
n":"image contains headers
n";
$exif=exif_read_data('tests/test2.jpg',0,true); //Read file 2 information
echo "test2.jpg:
n"; //Output file name
foreach($exif as $key=>$section) //Loop to read information
{
foreach($section as $name=>$val)
{
echo "$key.$name:$val
n";
}
}
/*
test1.jpg:
no header data found.
test2.jpg:
file.filename: test2.jpg
file.filedatetime: 1017666176
file.filesize: 1240
file.filetype: 2
file.sectionsfound: any_tag, ifd0, thumbnail, comment
computed.html: width="1" height="1"
computed.height: 1
computed.width: 1
computed.iscolor: 1
computed.byteordermotorola: 1
computed.usercomment: exif test image.
computed.usercommentencoding: ascii
computed.copyright: photo (c) m.boerger, edited by m.boerger.
computed.copyright.photographer: photo (c) m.boerger
computed.copyright.editor: edited by m.boerger.
ifd0.copyright: photo (c) m.boerger
ifd0.usercomment: ascii
thumbnail.jpeginterchangeformat: 134
thumbnail.jpeginterchangeformatlength: 523
comment.0: comment #1.
comment.1: comment #2.
comment.2: comment #3end
thumbnail.jpeginterchangeformat: 134
thumbnail.thumbnail.height: 1
thumbnail.thumbnail.height: 1

//*/

$index="1"; //Define index
$string=exif_tagname($index); //Get the header information of the image index
echo $string; //Output result

//

if(array_key_exists('file',$_request))
{
$image=exif_thumbnail($_request['file'],$width,$height,$type); //Get the thumbnail of the file
}
else                       // If the array does not have the corresponding key value
{
$image=false; //Return error
}
if($image!==false) //If it returns true
{
header("content-type:".image_type_to_mime_type($type)); //Send header file
echo $image; //Output thumbnail
exit; //End php tutorial code
}
else                    //If an error is returned
{
echo "no thumbnail available"; //Output information
}