On the order in your admin: the order note and the order’s metafields hold the photo link or text, and the order gets a tag.
Shopify’s Order edited email and packing slip don’t show it on their own; the app gives you a snippet to paste into each, under Emails and packing slips.
Still stuck?
Open the app in your Shopify admin, go to Help and click Chat with us, or email [email protected] with your store’s myshopify.com address.