Using WordPress ‘jpeg_quality’ PHP filter

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The jpeg_quality WordPress PHP Filter allows you to change the JPEG compression quality for backward compatibility.

Usage

add_filter('jpeg_quality', 'your_custom_function', 10, 2);

function your_custom_function($quality, $context) {
    // your custom code here
    return $quality;
}

Parameters

  • $quality (int): Quality level between 0 (low) and 100 (high) of the JPEG.
  • $context (string): Context of the filter, can be either ‘image_resize’ or ‘edit_image’.

More information

See WordPress Developer Resources: jpeg_quality

Examples

Increase JPEG quality to 90

Increase the JPEG quality to 90 for both resizing and editing images.

add_filter('jpeg_quality', 'increase_jpeg_quality', 10, 2);

function increase_jpeg_quality($quality, $context) {
    $quality = 90;
    return $quality;
}

Set different JPEG quality for resizing and editing

Set the JPEG quality to 80 for image resizing and 90 for image editing.

add_filter('jpeg_quality', 'set_different_jpeg_quality', 10, 2);

function set_different_jpeg_quality($quality, $context) {
    if ($context == 'image_resize') {
        $quality = 80;
    } elseif ($context == 'edit_image') {
        $quality = 90;
    }
    return $quality;
}

Decrease JPEG quality based on user role

Decrease the JPEG quality to 70 for users with the ‘subscriber’ role.

add_filter('jpeg_quality', 'decrease_jpeg_quality_for_subscribers', 10, 2);

function decrease_jpeg_quality_for_subscribers($quality, $context) {
    if (current_user_can('subscriber')) {
        $quality = 70;
    }
    return $quality;
}

Increase JPEG quality for specific image sizes

Increase the JPEG quality to 95 for ‘large’ image sizes.

add_filter('jpeg_quality', 'increase_jpeg_quality_for_large_images', 10, 2);

function increase_jpeg_quality_for_large_images($quality, $context) {
    $size = 'large';
    if ($context == 'image_resize' && $size == 'large') {
        $quality = 95;
    }
    return $quality;
}

Set JPEG quality based on custom image sizes

Set the JPEG quality based on custom image sizes registered with add_image_size.

add_filter('jpeg_quality', 'set_jpeg_quality_based_on_custom_sizes', 10, 2);

function set_jpeg_quality_based_on_custom_sizes($quality, $context) {
    global $_wp_additional_image_sizes;
    if (isset($_wp_additional_image_sizes['custom_size'])) {
        $custom_size_quality = 85;
        $quality = $custom_size_quality;
    }
    return $quality;
}