in generative fill my add button doesn't allow me to bring up an photo I want to use in an area I "painted"

I have a 3D rendering of a retail store interior. I prompted product to be added to the shelfves down one wall. It went Half-way. I prompted 15 times for it to continue and nothing worked. Moved to a back wall and prompted for “hanging clothing” a dozen times and nothing cam close. I downloaded a picture I wanted to add in Generative Fill. I painted the area and went to the add button to download that picture into firefly and the button does nothing