Judging by the other strings (E & A), there appears to be a definite 'kink' where these run across the nut slot. To me it looks like the nut needs some attention. As you say, bit difficult to see from the photo, however, unless you know how to shape a DB nut, I suggest speaking to some local repairers / luthiers first. Shaping a nut shouldn't be more than around £20 - £25 and will definitely be cheaper than breaking strings.