Problem:

The customer created a custom post field for images but was unable to upload AVIF format files to the field, despite AVIF images being supported elsewhere in their WordPress media library. They requested a solution to enable AVIF uploads in Toolset's custom image field.

Solution:

A code snippet was provided to extend the valid image file types for Toolset, allowing AVIF images. The customer added this code to their theme’s functions.php file or within Toolset > Settings >

function allow_avif_in_toolset( $valid_extensions ) {
    // Add AVIF to the list of valid extensions
    $valid_extensions[] = 'avif';
    return $valid_extensions;
}
add_filter( 'toolset_valid_image_extentions', 'allow_avif_in_toolset' );

This code successfully enabled the AVIF format in the custom image field, allowing the customer to upload AVIF images as intended.