It's wrong because they (whoever made the figure) are counting "zero" as the first cycle. But that's not how cycles work.

Consider the top left figure, where it says 4 cycles per second = 3 hz. Yes, the wave has four crests in the defined time period, but the first one doesn't count as a cycle. A cycle is when you go from one crest to the next. There are only three cycles in that figure (indicated as λ_{1}), not four as specified.

Imagine it this way. Let's say you exit your house and walk around your block repeatedly for exactly one hour. During the hour you pass your house twice and arrive back at your house exactly at the hour point. In total you were at your hour four times during the hour (the initial one, passing twice, and at the end), but you only made three cycles around the block. Just coming out of the door is not a cycle. A cycle is starting at your door, going all the way around, and arriving back at the starting point.