How do I add an image into php code (my related posts widget)?

Hi, I have no idea how to use php (apologies in advance for the stupid questions), but is it possible to add a custom icon into my Related Posts widget?

I’m using Contextual Related Posts, and I’d love to add a hand-drawn arrow image after the Related Posts headline, like this.

(I shopped the arrow in in this picture, but that’s how I’d like it to look)

What code should I use and where do I insert it..? I tried the following (incredibly bad) code, inserted somewhat haphazardly into the widget code: (my code is just the close php tag, the img src, and the open php tag)

if ( $results ) {
		$loop_counter = 0;

		$output .= crp_heading_title( $args );?> <img src=" https://www.whycatwhy.com/wp-content/uploads/2016/02/arrow-e1455034570971.png"/><?php

		$output .= crp_before_list( $args );

Any help would be greatly appreciated. Thank you!