Thanks for the code. The issue may be as simple as changing:
$projectimages = the_sub_field('pro_impressions');
$projectimages = get_sub_field('pro_impressions');
Make sure all the field names are correct, and this should work just fine.
As for the
wp_reset_postdata() function, this is a WP function only to be used after a custom WP_Query loop, not a repeater field loop.