The Add image button is a custom microflow? My assumption is that you forgot to set the reference.
Make it a custom microflow behind the button and pass the Engineer as parameter. Check via the reference if a Photo object exists otherwise create one and set the reference with the Engineer. Then pass this Photo object to the page you already created. So if you found a picture pas that object if you created a new Photo object you have to pass that one.
Another option would be to already incorporate the picture in the engineer object. But then you have to make sure that when you create a new Engineer you also create and set the reference of the new Photo object.
Regards,
Ronald