Trigger on modal open ?

Hello everyone,
thanks for your amazing plugin,
i have a question, i am using ur plugin using shortcode
and i am trying to adjust modal height to fit the image height,
I don’t know if this is the best practice,

i am trying to do this:

var image = $('.modal-window-content p img');
var image_height = image.height();
$('.wow-modal-window').height(image_height);

but, how can i trigger when the modal is loaded?