Wordpress ACF中继器图像调整大小

I am trying to resize an image coming from the Advanced Custom Fields repeater field with no success.

I have set up a basic non-repeater image field in the exact same way elsewhere on the page and it works perfectly.

So I have the image size set up in the functions.php:

add_image_size( 'bio-size', 400, 260, true );

Then in the template I have:

<?php while( have_rows('bio') ): the_row();

  $bioImgObj = get_sub_field('bio_image');
  $bioImgSize = 'bio-size';
  $bioImgUrl = $bioImgObj['sizes'][$bioImgSize];

?>

<img width="400" height="260" src="<?php echo $bioImgUrl; ?>"/>

This gives me the image, but does not resize it in any way.

When using ACF, or general WordPress file uploads, modifying image sizes or other configs for files after upload wont affect already uploaded files because the files are processed on upload.