function file_validate_is_image

Checks that the file is recognized as a valid image.

Parameters

\Drupal\file\FileInterface $file: A file entity.

Return value

array An empty array if the file is a valid image or an array containing an error message if it's not.

See also

hook_file_validate()

File

core/modules/file/file.module, line 439

Code

function file_validate_is_image(FileInterface $file) {
    $errors = [];
    $image_factory = \Drupal::service('image.factory');
    $image = $image_factory->get($file->getFileUri());
    if (!$image->isValid()) {
        $supported_extensions = $image_factory->getSupportedExtensions();
        $errors[] = t('The image file is invalid or the image type is not allowed. Allowed types: %types', [
            '%types' => implode(', ', $supported_extensions),
        ]);
    }
    return $errors;
}