Try this and tell me what you get
if(have_rows('image_test_repeater')) :
while(have_rows('image_test_repeater')) : $rowHold = the_row();
var_dump($rowHold);
echo("BEFORE ");
if(get_sub_field('test_image_file')) {
echo 'IMAGE EXISTS ID = '.get_sub_field('test_image_file');
echo("<img src='");
the_sub_field('test_image_file');
echo("'>'");
}
echo(" AFTER");
endwhile;
endif;