Get a specified number of images in a post's gallery by post ID

functions.php

function get_first_images($post, $count){
		$post = get_post($post);
		if ( ! has_shortcode( $post->post_content, 'gallery' ) ){
			return array();
		}
		$galleries = array();
		// find and separate out what kind of shortcode we are looking at 
		if ( preg_match_all( '/' . get_shortcode_regex() . '/s', $post->post_content, $matches, PREG_SET_ORDER ) ) {
		
			foreach ( $matches as $shortcode ) {
			
				if ( 'gallery' === $shortcode[2] ) {
				
					$srcs = array();
					$gallery_img_ids = $shortcode[3]; 
					preg_match_all('/([0-9]+)/', $gallery_img_ids, $foundMatches);
					$img_ids = $foundMatches[0];
					
					if ( ! empty( $img_ids ) ) {
						$i = 0;
						foreach ( $img_ids as $img ){
							$i++; 
							$gallery_image =  wp_get_attachment_image_src(intval($img), 'thumbnail'); 
							$srcs[] = $gallery_image[0];
							if($i==$count) break;
						}
					
					}
					return $srcs;
				}
			}
		}
	
}

template_file.php

// pass post ID and how many images you want to get
$gallery_imgs = get_first_images( $pid, 4);

if ($gallery_imgs) {
		    foreach ($gallery_imgs as $img) {
		   		echo '<img src="'. $img.'"/>';
			}
		}