sure. you need to count the images of the gallery, get the difference to 4, and loop through gallery but echo only the last 4 (the others loop without echo)
something like this:
$images = get_field('gallery');
$count= count($images);
if ($count > 4){
$i = 0 - $count + 4;
} else { $i=0;}
foreach( $images as $image ):
$i++;
if ($i > 0){
echo $image['url'];
}
endforeach;
not sure if code is correct, but it should help to made a correct one
