Nokia 4.2 Data and photos missing

A friend tried to transfer photos from an sd card to a phone, since then all the data and photos on the phone have been inaccessible. We have managed to get somethings back from the sd card but some of the photos are only half of the picture and there is a lot still missing, so the presumption is they are on the phone which we have tried rooting (which failed quite quickly), scanning and recovering which works up until it gets to photos like its locked itself and if we try to install anything on the phone it says its full even though there 15 GB left so the photos must still be there and we can’t access any files in windows explorer just nothing appears when we enter the phones folder. Also we are unable to take pictures they appear in the recent in the bottom right but are not in the gallery afterwards.

Any idea how we can get access to these photos?

Thanks in advance.