From the third picture, the rule is that the sum of the number of branches in the first picture plus the number of branches in the previous picture is multiplied by 2.

That is, the number of branches in the third graph = ~ 1+3 ~× 2 = 8.

The number of branches in the fourth graph = ~ 1+8 ~× 2 = 18.

The number of branches in the fifth graph = ~ 1+ 18 ~× 2 = 38.

The number of branches in the sixth graph = ~ 1+38 ~× 2 = 78.

The number of branches in the seventh graph = ~ 1+78 ~× 2 = 158.

So the seventh picture has more branches than the sixth picture 158-78 = 80.