imagesx parameter warning

I’m seeing the following error:

Warning: imagesx() expects parameter 1 to be resource, boolean given in /home/content/17/4076817/html/wp-content/plugins/wonderm00ns-simple-facebook-open-graph-tags/wonderm00n-open-graph.php on line 611

Looks like there is no conditional on $im. I solved this by changing line 610 to if ($im && $x=imagesx($im)) { but I’m not sure if that’s the best solution.

https://wordpress.org/plugins/wonderm00ns-simple-facebook-open-graph-tags/