Approaches to Web Development for Bioinformatics

Medical Computing > Web Development for Bioinformatics > Web Development > PHP > Image Metadata

Image Metadata

PHP scripts can be used to find image metadata information. To do this PHP must be configured to load the EXIF libary. The PHP manual ³⁵ gives details on the use of the use of the EXIF library.

Here is a program that finds metadata from an image file and prints it out by dumping the array contents.

PHP

<?php

$exif = exif_read_data('../images/230px-Heart-and-lungs.jpg');
print_r($exif);

The program read the image data with the function exif_read_data($fileName). The program output is

Program Output

Array (

[FileName] => 230px-Heart-and-lungs.jpg
[FileDateTime] => 1160236437
[FileSize] => 16304
[FileType] => 2
[MimeType] => image/jpeg
[SectionsFound] => [COMPUTED] => Array (

[html] => width="230" height="224" [Height] => 224 [Width] => 230 [IsColor] => 1

)

The EXIF library also has a function exif_thumbnail() to extract an embedded thumbnail image from a JPG or TIFF file. this is demonstrated by the following program.

PHP

<?php

$thumbnail = exif_thumbnail('../images/redbloodcells.jpg', $width, $height, $type);
if ($thumbnail != false) {

$mime = image_type_to_mime_type($type);
header("Content-type: $mime");
print($thumbnail);

} else {

print("No thumbnail available.");

}

The program output is shown below.

EXIF Extracted Thumbnail

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