that pot looks way too small. raspberries have long roots...im not even sure if they would work in pots. you should go over to the container gardening section and ask your question there. if they are able to grow in pots, im guessing you need one about 5x that size.

I have some of mine in pots and in ground. Potted the smallest one which I'm holding for a friend, is in 5gal nursery pot has 2 tall canes and some small ones and has only given a handful of berries. Others are in barrels as planters 24in diameter or 34x23 long cut and I pick 1-2cups, 2x a day to keep birds from getting them. The runners need to spread and send up multiple canes to get any decent fruit but its definitely do-able in a container even without buying a "brazelberry" type.