Oh, I see the problem...
This needs to say
"dstRemote": "album/Uploads/googlelogo_color_272x92dp.png",
So you need to modify your curl like this
curl -X POST "http://127.0.0.1:5572/operations/copyfile?srcFs=/&srcRemote=/home/user/googlelogo_color_272x92dp.png&dstFs=gphotos:&dstRemote=album/Uploads/googlelogo_color_272x92dp.png"