I’m unable to call img path using single quotes in an array?

You’re trying to use PHP tags while inside a string:

'<img src="https://wordpress.stackexchange.com/questions/302344/<?php bloginfo("template_directory'); ?>/images/social/facebook-share.png" />'

You need to instead use concatenation:

'<img src="' . esc_url( get_bloginfo('template_directory') ) . '/images/social/facebook-share.png" />'

Or my personal favorite, sprintf():

sprintf(
    '<img src="https://wordpress.stackexchange.com/questions/302344/%1$s/images/social/facebook-share.png" />',
    esc_url( get_bloginfo('template_directory') )
);