You could amend the print_end code, so that the bed does not move downwards but remains visible for the camera. You can find the code for the print_end macro in fluidd.cfg, Whatever you do here, at your own risk…
This issue was mentioned by two users before. I passed it to the product manager, and they plan to address it in a future update—directly taking a photo with the camera during the descent, then moving to the bottom.