On my boat I just finished replacing the cutlass (very worn), the shaft log (worn out where prop shaft had contacted it due to mis-alignment) and stuffing box, as well as engine rubber mounts.
I also had a vibration problem. Could have been the cutlass, but the shaft was also contacting the stainless shaft log (it was also corroded and had a slow leak), which could have caused vibrations.
To test you cutlass, grab the prop and shake it up and down and sideways to test for cutlass play. It should be tight or just have very minor play. It does look like you shaft is hitting the edge of what looks like a stuffing box or dripless shaft seal
. As others have said, check your engine mounts and then do an alignment. The shaft should be aligned so that it is centered in the shaft log (cutlass strut needs to be correct for this to happen- hopefully it is), then the engine coupling needs to be aligned with the shaft coupling. The couplings need to be parallel and centered.
What is the shaft log in the pic?