wp_read_image_metadata() WordPress Function

The wp_read_image_metadata() function reads the image's EXIF data and stores it in an array. This function can be used to return the EXIF data for an image attachment.

wp_read_image_metadata( string $file ) #

Get extended image metadata, exif or iptc as available.

Contents

Description

Retrieves the EXIF metadata aperture, credit, camera, caption, copyright, iso created_timestamp, focal_length, shutter_speed, and title.

The IPTC metadata that is retrieved is APP13, credit, byline, created date and time, caption, copyright, and title. Also includes FNumber, Model, DateTimeDigitized, FocalLength, ISOSpeedRatings, and ExposureTime.

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Parameters

$file

(string)(Required)

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Return

(array|false) Image metadata array on success, false on failure.

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More Information

Additional note to Return

The elements returned in the array are:

["aperture"]
(string) Set to the EXIF FNumber field.

["credit"]
(string) Set to the first non-empty value found by looking through the following fields:

  1. IPTC Credit field (2#110)
  2. IPTC Creator field (2#080)
  3. EXIF Artist field
  4. EXIF Author field

["camera"]
(string) Set to the EXIF Model field.

["caption"]
(string) Set to a non-empty value of one of the following fields (see source code for the precise logic involved):

  1. IPTC Description field (2#120)
  2. EXIF UserComment field if [“title”] is unset AND EXIF:ImageDescription is less than 80 characters
  3. EXIF ImageDescription field if [“title”] is set OR EXIF:ImageDescription is more than 80 characters
  4. EXIF Comments field if [“title”] does not equal EXIF:Comments

["created_timestamp"]
(string) Set to the first non-empty value found by looking through the following fields:

  1. EXIF field DateTimeDigitized
  2. IPTC Date and Time fields (2#055 and 2#060)

["copyright"]
(string) Set to the first non-empty value found by looking through the following fields:

  1. IPTC Copyright field (2#116)
  2. EXIF Copyright field

["focal_length"]
(string) Set to the EXIF FocalLength field.

["iso"]
(string) Set to the EXIF ISOSpeedRatings field.

["shutter_speed"]
(string) Set to the EXIF ExposureTime field.

["title"]
(string) Set to the first non-empty value found by looking through the following fields:

  1. IPTC Headline field (2#105)
  2. IPTC Title field (2#005)
  3. IPTC Description field (2#120) but only if less than 80 characters
  4. EXIF Title field
  5. EXIF ImageDescription field but only if less than 80 characters

The (2#nnn) value shown after each IPTC field (above) is the key of the array returned by PHP’s iptcparse function for that particular IPTC field.

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Source

File: wp-admin/includes/image.php

function wp_read_image_metadata( $file ) {
	if ( ! file_exists( $file ) ) {
		return false;
	}

	list( , , $image_type ) = wp_getimagesize( $file );

	/*
	 * EXIF contains a bunch of data we'll probably never need formatted in ways
	 * that are difficult to use. We'll normalize it and just extract the fields
	 * that are likely to be useful. Fractions and numbers are converted to
	 * floats, dates to unix timestamps, and everything else to strings.
	 */
	$meta = array(
		'aperture'          => 0,
		'credit'            => '',
		'camera'            => '',
		'caption'           => '',
		'created_timestamp' => 0,
		'copyright'         => '',
		'focal_length'      => 0,
		'iso'               => 0,
		'shutter_speed'     => 0,
		'title'             => '',
		'orientation'       => 0,
		'keywords'          => array(),
	);

	$iptc = array();
	$info = array();
	/*
	 * Read IPTC first, since it might contain data not available in exif such
	 * as caption, description etc.
	 */
	if ( is_callable( 'iptcparse' ) ) {
		wp_getimagesize( $file, $info );

		if ( ! empty( $info['APP13'] ) ) {
			// Don't silence errors when in debug mode, unless running unit tests.
			if ( defined( 'WP_DEBUG' ) && WP_DEBUG
				&& ! defined( 'WP_RUN_CORE_TESTS' )
			) {
				$iptc = iptcparse( $info['APP13'] );
			} else {
				// phpcs:ignore WordPress.PHP.NoSilencedErrors -- Silencing notice and warning is intentional. See https://core.trac.wordpress.org/ticket/42480
				$iptc = @iptcparse( $info['APP13'] );
			}

			if ( ! is_array( $iptc ) ) {
				$iptc = array();
			}

			// Headline, "A brief synopsis of the caption".
			if ( ! empty( $iptc['2#105'][0] ) ) {
				$meta['title'] = trim( $iptc['2#105'][0] );
				/*
				* Title, "Many use the Title field to store the filename of the image,
				* though the field may be used in many ways".
				*/
			} elseif ( ! empty( $iptc['2#005'][0] ) ) {
				$meta['title'] = trim( $iptc['2#005'][0] );
			}

			if ( ! empty( $iptc['2#120'][0] ) ) { // Description / legacy caption.
				$caption = trim( $iptc['2#120'][0] );

				mbstring_binary_safe_encoding();
				$caption_length = strlen( $caption );
				reset_mbstring_encoding();

				if ( empty( $meta['title'] ) && $caption_length < 80 ) {
					// Assume the title is stored in 2:120 if it's short.
					$meta['title'] = $caption;
				}

				$meta['caption'] = $caption;
			}

			if ( ! empty( $iptc['2#110'][0] ) ) { // Credit.
				$meta['credit'] = trim( $iptc['2#110'][0] );
			} elseif ( ! empty( $iptc['2#080'][0] ) ) { // Creator / legacy byline.
				$meta['credit'] = trim( $iptc['2#080'][0] );
			}

			if ( ! empty( $iptc['2#055'][0] ) && ! empty( $iptc['2#060'][0] ) ) { // Created date and time.
				$meta['created_timestamp'] = strtotime( $iptc['2#055'][0] . ' ' . $iptc['2#060'][0] );
			}

			if ( ! empty( $iptc['2#116'][0] ) ) { // Copyright.
				$meta['copyright'] = trim( $iptc['2#116'][0] );
			}

			if ( ! empty( $iptc['2#025'][0] ) ) { // Keywords array.
				$meta['keywords'] = array_values( $iptc['2#025'] );
			}
		}
	}

	$exif = array();

	/**
	 * Filters the image types to check for exif data.
	 *
	 * @since 2.5.0
	 *
	 * @param int[] $image_types Array of image types to check for exif data. Each value
	 *                           is usually one of the `IMAGETYPE_*` constants.
	 */
	$exif_image_types = apply_filters( 'wp_read_image_metadata_types', array( IMAGETYPE_JPEG, IMAGETYPE_TIFF_II, IMAGETYPE_TIFF_MM ) );

	if ( is_callable( 'exif_read_data' ) && in_array( $image_type, $exif_image_types, true ) ) {
		// Don't silence errors when in debug mode, unless running unit tests.
		if ( defined( 'WP_DEBUG' ) && WP_DEBUG
			&& ! defined( 'WP_RUN_CORE_TESTS' )
		) {
			$exif = exif_read_data( $file );
		} else {
			// phpcs:ignore WordPress.PHP.NoSilencedErrors -- Silencing notice and warning is intentional. See https://core.trac.wordpress.org/ticket/42480
			$exif = @exif_read_data( $file );
		}

		if ( ! is_array( $exif ) ) {
			$exif = array();
		}

		if ( ! empty( $exif['ImageDescription'] ) ) {
			mbstring_binary_safe_encoding();
			$description_length = strlen( $exif['ImageDescription'] );
			reset_mbstring_encoding();

			if ( empty( $meta['title'] ) && $description_length < 80 ) {
				// Assume the title is stored in ImageDescription.
				$meta['title'] = trim( $exif['ImageDescription'] );
			}

			if ( empty( $meta['caption'] ) && ! empty( $exif['COMPUTED']['UserComment'] ) ) {
				$meta['caption'] = trim( $exif['COMPUTED']['UserComment'] );
			}

			if ( empty( $meta['caption'] ) ) {
				$meta['caption'] = trim( $exif['ImageDescription'] );
			}
		} elseif ( empty( $meta['caption'] ) && ! empty( $exif['Comments'] ) ) {
			$meta['caption'] = trim( $exif['Comments'] );
		}

		if ( empty( $meta['credit'] ) ) {
			if ( ! empty( $exif['Artist'] ) ) {
				$meta['credit'] = trim( $exif['Artist'] );
			} elseif ( ! empty( $exif['Author'] ) ) {
				$meta['credit'] = trim( $exif['Author'] );
			}
		}

		if ( empty( $meta['copyright'] ) && ! empty( $exif['Copyright'] ) ) {
			$meta['copyright'] = trim( $exif['Copyright'] );
		}
		if ( ! empty( $exif['FNumber'] ) && is_scalar( $exif['FNumber'] ) ) {
			$meta['aperture'] = round( wp_exif_frac2dec( $exif['FNumber'] ), 2 );
		}
		if ( ! empty( $exif['Model'] ) ) {
			$meta['camera'] = trim( $exif['Model'] );
		}
		if ( empty( $meta['created_timestamp'] ) && ! empty( $exif['DateTimeDigitized'] ) ) {
			$meta['created_timestamp'] = wp_exif_date2ts( $exif['DateTimeDigitized'] );
		}
		if ( ! empty( $exif['FocalLength'] ) ) {
			$meta['focal_length'] = (string) $exif['FocalLength'];
			if ( is_scalar( $exif['FocalLength'] ) ) {
				$meta['focal_length'] = (string) wp_exif_frac2dec( $exif['FocalLength'] );
			}
		}
		if ( ! empty( $exif['ISOSpeedRatings'] ) ) {
			$meta['iso'] = is_array( $exif['ISOSpeedRatings'] ) ? reset( $exif['ISOSpeedRatings'] ) : $exif['ISOSpeedRatings'];
			$meta['iso'] = trim( $meta['iso'] );
		}
		if ( ! empty( $exif['ExposureTime'] ) ) {
			$meta['shutter_speed'] = (string) $exif['ExposureTime'];
			if ( is_scalar( $exif['ExposureTime'] ) ) {
				$meta['shutter_speed'] = (string) wp_exif_frac2dec( $exif['ExposureTime'] );
			}
		}
		if ( ! empty( $exif['Orientation'] ) ) {
			$meta['orientation'] = $exif['Orientation'];
		}
	}

	foreach ( array( 'title', 'caption', 'credit', 'copyright', 'camera', 'iso' ) as $key ) {
		if ( $meta[ $key ] && ! seems_utf8( $meta[ $key ] ) ) {
			$meta[ $key ] = utf8_encode( $meta[ $key ] );
		}
	}

	foreach ( $meta['keywords'] as $key => $keyword ) {
		if ( ! seems_utf8( $keyword ) ) {
			$meta['keywords'][ $key ] = utf8_encode( $keyword );
		}
	}

	$meta = wp_kses_post_deep( $meta );

	/**
	 * Filters the array of meta data read from an image's exif data.
	 *
	 * @since 2.5.0
	 * @since 4.4.0 The `$iptc` parameter was added.
	 * @since 5.0.0 The `$exif` parameter was added.
	 *
	 * @param array  $meta       Image meta data.
	 * @param string $file       Path to image file.
	 * @param int    $image_type Type of image, one of the `IMAGETYPE_XXX` constants.
	 * @param array  $iptc       IPTC data.
	 * @param array  $exif       EXIF data.
	 */
	return apply_filters( 'wp_read_image_metadata', $meta, $file, $image_type, $iptc, $exif );

}

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Uses

Uses
UsesDescription
wp-includes/media.php:wp_getimagesize()

Allows PHP’s getimagesize() to be debuggable when necessary.

wp-includes/kses.php:wp_kses_post_deep()

Navigates through an array, object, or scalar, and sanitizes content for allowed HTML tags for post content.

wp-admin/includes/image.php:wp_exif_frac2dec()

Convert a fraction string to a decimal.

wp-admin/includes/image.php:wp_exif_date2ts()

Convert the exif date format to a unix timestamp.

wp-admin/includes/image.php:wp_read_image_metadata_types

Filters the image types to check for exif data.

wp-admin/includes/image.php:wp_read_image_metadata

Filters the array of meta data read from an image’s exif data.

wp-includes/formatting.php:seems_utf8()

Checks to see if a string is utf8 encoded.

wp-includes/functions.php:mbstring_binary_safe_encoding()

Set the mbstring internal encoding to a binary safe encoding when func_overload is enabled.

wp-includes/functions.php:reset_mbstring_encoding()

Reset the mbstring internal encoding to a users previously set encoding.

wp-includes/plugin.php:apply_filters()

Calls the callback functions that have been added to a filter hook.

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Used By

Used By
Used ByDescription
wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php:WP_REST_Attachments_Controller::insert_attachment()

Inserts the attachment post in the database. Does not update the attachment meta.

wp-admin/includes/image.php:wp_create_image_subsizes()

Creates image sub-sizes, adds the new data to the image meta sizes array, and updates the image metadata.

wp-admin/includes/media.php:media_handle_upload()

Saves a file submitted from a POST request and create an attachment post for it.

wp-admin/includes/media.php:media_handle_sideload()

Handles a side-loaded file in the same way as an uploaded file is handled by media_handle_upload().

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Changelog

Changelog
VersionDescription
2.5.0Introduced.
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