WooCommerce Async Hook after order is placed

My Scenario: During the shopping, a user uploads an image to the server, this image needs to be processed (resizing, trimming) but this process needs too much time when done synchronously. What I need: A special hook to be able to run asynchronous tasks after a new order is placed. So when a new order is placed, you see the thank you page like "We received your order". I need to be able to run my image processing code at this position, so after the order is placed and the user doesn't have to wait for the processing, it must run in the background. An important feature is that the new order emails for the customer and the admin need to be sent AFTER this custom action. In the standard process, these emails are sent before showing the "thank you" page, this needs to be changed. Summary: I need a possibility to run async code after an order is placed which runs without the user waiting for it. This possibility needs to be able to run custom code and trigger the new order emails after the custom code is done.