(PHP 4 >= 4.2.0, PHP 5)
exif_tagname — Get the header name for an index
The Tag ID for which a Tag Name will be looked up.
Returns the header name, or FALSE if index is not a defined EXIF tag id.
Example #1 exif_tagname() example 以上例程会输出：
<?php
echo "256: ".exif_tagname(256).PHP_EOL;
echo "257: ".exif_tagname(257).PHP_EOL;
?>
256: ImageWidth
257: ImageLength