WordPress Function Spotlight: wp_get_attachment_image_src()

WordPress is a versatile content management system that offers a wide range of functions and features to enhance the functionality of your website. One such function is wp_get_attachment_image_src(), which allows you to retrieve an image to represent an attachment. In this article, we will take a deep dive into this function, exploring its parameters, return values, source code, and practical uses.

1. Introduction

The wp_get_attachment_image_src() function is a powerful tool in the WordPress developer’s toolkit. It allows you to retrieve an image to represent an attachment, providing you with the necessary data to display the image on your website. Whether you’re building a custom theme or developing a plugin, this function can come in handy when working with image attachments.

2. Parameters

The wp_get_attachment_image_src() function accepts three parameters:

  • $attachment_id (int, required): The ID of the image attachment.
  • $size (string|int[], optional): The desired image size. This parameter accepts any registered image size name or an array of width and height values in pixels.
  • $icon (bool, optional): Specifies whether the image should fall back to a mime type icon.

By providing the appropriate values for these parameters, you can customize the output of the function to suit your specific requirements.

3. Return Value

The wp_get_attachment_image_src() function returns an array or false, depending on whether the image is available or not. If an image is available, the return value is an array containing the following information:

  • Image source URL.
  • Image width in pixels.
  • Image height in pixels.
  • Whether the image is a resized image.

In case no image is available, the function returns false.

4. Source Code

The source code for the wp_get_attachment_image_src() function can be found in the wp-includes/media.php file. Below is an excerpt of the relevant code:

function wp_get_attachment_image_src($attachment_id, $size = 'thumbnail', $icon = false) {
    // Get a thumbnail or intermediate image if there is one.
    $image = image_downsize($attachment_id, $size);

    // Handle fallback to mime type icon if necessary.
    if (!$image) {
        $src = false;
        if ($icon) {
            $src = wp_mime_type_icon($attachment_id);
            // Additional code here to handle icon directory and image dimensions.
        if ($src && $width && $height) {
            $image = array($src, $width, $height, false);

    // Filter and return the image source.
    return apply_filters('wp_get_attachment_image_src', $image, $attachment_id, $size, $icon);

This code snippet gives you a glimpse into how the function retrieves and processes the image data.

5. Hooks

The wp_get_attachment_image_src() function provides two hooks that allow you to modify its behavior:

  • icon_dir: This filter allows you to modify the icon directory path.
  • wp_get_attachment_image_src: This filter enables you to modify the attachment image source result.

By utilizing these hooks, you can customize the function to better suit your needs.

6. Related Functions

The wp_get_attachment_image_src() function is closely related to several other WordPress functions that deal with image attachments. These functions include:

  • wp_getimagesize(): Allows PHP’s getimagesize() to be debuggable when necessary.
  • image_downsize(): Scales an image to fit a particular size.
  • wp_mime_type_icon(): Retrieves the icon for a MIME type or attachment.
  • wp_basename(): Provides an i18n-friendly version of basename().
  • apply_filters(): Calls the callback functions that have been added to a filter hook.

These functions work together to handle various aspects of working with image attachments in WordPress.

7. Uses

The wp_get_attachment_image_src() function has a variety of practical uses. Here are a few examples:

  • Displaying a specific image size: By specifying the desired image size, you can retrieve images in different sizes and display them appropriately on your website.
  • Creating custom image galleries: The function allows you to retrieve image data for multiple attachments, enabling you to create custom image galleries with ease.
  • Building responsive designs: With the ability to retrieve images of different sizes, you can build responsive designs that adapt to different screen sizes and resolutions.

These are just a few of the many ways in which you can leverage the wp_get_attachment_image_src() function to enhance your WordPress website.

8. Used By

The wp_get_attachment_image_src() function is used by various other WordPress functions and classes. Some notable examples include:

  • WP_REST_Attachments_Controller::prepare_item_for_response(): This function prepares a single attachment output for response in the REST API.
  • get_oembed_response_data_rich(): This function filters the oEmbed response data to return an iframe embed code.
  • wp_get_attachment_image_srcset(): Retrieves the value for an image attachment’s ‘srcset’ attribute.
  • wp_get_attachment_image_sizes(): Retrieves the value for an image attachment’s ‘sizes’ attribute.

These functions and classes rely on wp_get_attachment_image_src() to retrieve image data for various purposes.

9. Changelog

The wp_get_attachment_image_src() function was introduced in WordPress version 2.5.0. Since then, it has undergone various changes and improvements. For a complete overview of the function’s changelog, refer to the official WordPress documentation.

10. User Contributed Notes

The WordPress community has contributed valuable insights and notes regarding the wp_get_attachment_image_src() function. One notable contribution highlights the discrepancy between the keys mentioned in the documentation and the actual indexes returned by the function. This note suggests making the return values clearer and providing additional information on the ‘is_intermediate’ array. These user-contributed notes further enrich the understanding and usage of the wp_get_attachment_image_src() function.

In conclusion, wp_get_attachment_image_src() is a versatile and essential function in the WordPress ecosystem. It allows developers to retrieve image data for attachments, enabling them to create dynamic and visually appealing websites. By understanding the function’s parameters, return values, and practical uses, you can harness its power to enhance your WordPress projects. Remember to explore the WordPress documentation and community resources for further information and insights on this function and related topics.

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