Get attachment next and previous by author only

Hi @Jeremy Love:

Good question! And it’s a good question because there do not appear to be any hooks to allow you to write code to filtering by author.

Sadly that means to copy their copy to make your own functions so you can make the required 1 line change (in this case, it’s 'post_author' => $post->post_author,). Here are functions you should be able to use:

function yoursite_previous_image_link($size="thumbnail", $text = false) {
  yoursite_adjacent_image_link(true, $size, $text);
}
function yoursite_next_image_link($size="thumbnail", $text = false) {
  yoursite_adjacent_image_link(false, $size, $text);
}
function yoursite_adjacent_image_link($prev=true,$size="thumbnail",$text=false) {
  global $post;
  $post = get_post($post);
  $attachments = array_values(get_children( array(
   'post_author' => $post->post_author,
   'post_parent' => $post->post_parent, 
   'post_status' => 'inherit', 
   'post_type' => 'attachment', 
   'post_mime_type' => 'image', 
   'order' => 'ASC', 
   'orderby' => 'menu_order ID'
   )));

  foreach ( $attachments as $k => $attachment )
    if ( $attachment->ID == $post->ID )
      break;
  $k = $prev ? $k - 1 : $k + 1;
  if ( isset($attachments[$k]) )
    echo wp_get_attachment_link($attachments[$k]->ID, $size, true, false, $text);
}