Actually that picture does demonstrate one of the most knackering features of walking in the Brecon Beacons. If you go up the hills you keep seeing what appears to be the summit only to find it is a ridge and there is another climb the other side of it and another beyond that and so on. The only other advice is watch out for the mist! It looks very pretty creeping up the next hillside and suddenly you are in the thick of it. Only answer is to sit down, have a warm drink and wait it out ~ if not broken limbs are the usual result. Once you reach the "Tops" the views are amazing and the quiet unbelievable, until the RAF come by of course, which they do fairly regularly.
This trio approaching RAF Valley (Anglesey) being a typical example of what passes over head and sometimes below you (if you have reached the "tops")